Process for preparing fondaparinux sodium and intermediates useful in the synthesis thereof

ABSTRACT

Processes for the synthesis of the Factor Xa anticoagulent Fondaparinux, and related compounds are described. Also described are protected pentasaccharide intermediates as well as efficient and scalable processes for the industrial scale production of Fondaparinux sodium by conversion of the protected pentasaccharide intermediates via a sequence of deprotection and sulfonation reactions.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/230,557, filed Jul. 31, 2009, which is incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates to processes for the synthesis of theFactor Xa anticoagulent Fondaparinux, and related compounds. Theinvention also relates to protected pentasaccharide intermediates and toan efficient and scalable process for the industrial scale production ofFondaparinux sodium by conversion of the protected pentasaccharideintermediates via a sequence of deprotection and sulfonation reactions.

BACKGROUND OF THE INVENTION

In U.S. Pat. No. 7,468,358, Fondaparinux sodium is described as the“only anticoagulant thought to be completely free of risk from HIT-2induction.” The biochemical and pharmacologic rationale for thedevelopment of a heparin pentasaccharide in Thromb. Res., 86(1), 1-36,1997 by Walenga et al. cited the recently approved syntheticpentasaccharide Factor Xa inhibitor Fondaparinux sodium. Fondaparinuxhas also been described in Walenga et al., Expert Opin. Investig. Drugs,Vol. 11, 397-407, 2002 and Bauer, Best Practice & Research ClinicalHematology, Vol. 17, No. 1, 89-104, 2004.

Fondaparinux sodium is a linear octasulfated pentasaccharide(oligosaccharide with five monosaccharide units) molecule having fivesulfate esters on oxygen (O-sulfated moieties) and three sulfates on anitrogen (N-sulfated moieties). In addition, Fondaparinux contains fivehydroxyl groups in the molecule that are not sulfated and two sodiumcarboxylates. Out of five saccharides, there are three glucosaminederivatives and one glucuronic and one L-iduronic acid. The fivesaccharides are connected to each other in alternate α and βglycosylated linkages (see FIG. 1).

Fondaparinux sodium is a chemically synthesized methoxy derivative ofthe natural pentasaccharide sequence, which is the active site ofheparin that mediates the interaction with antithrombin (Casu et al., J.Biochem., 197, 59, 1981). It has a challenging pattern of O- andN-sulfates, specific glycosidic stereochemistry, and repeating units ofglucosamines and uronic acids (Petitou et al., Progress in the Chemistryof Organic Natural Product, 60, 144-209, 1992).

The monosaccharide units comprising the Fondaparinux molecule arelabeled as per the convention in FIG. 1, with the glucosamine unit onthe right referred to as monosaccharide A and the next, an uronic acidunit to its left as B and subsequent units, C, D and E respectively. Thechemical synthesis of Fondaparinux starts with monosaccharides ofdefined structures that are themselves referred to as Monomers A2, B1,C, D and E, for differentiation and convenience, and they become thecorresponding monosaccharides in fondaparinux sodium.

Due to this complex mixture of free and sulfated hydroxyl groups, andthe presence of N-sulfated moieties, the design of a synthetic route toFondaparinux requires a careful strategy of protection and de-protectionof reactive functional groups during synthesis of the molecule.Previously described syntheses of Fondaparinux all adopted a similarstrategy to complete the synthesis of this molecule. This strategy canbe envisioned as having four stages. The strategy in the first stagerequires selective de-protection of five out of ten hydroxyl groups.During the second stage these five hydroxyls are selectively sulfonated.The third stage of the process involves the de-protection of theremaining five hydroxyl groups. The fourth stage of the process is theselective sulfonation of the 3 amino groups, in the presence of fivehydroxyl groups that are not sulfated in the final molecule. Thisstrategy can be envisioned from the following fully protectedpentasaccharide, also referred to as the late-stage intermediate.

In this strategy, all of the hydroxyl groups that are to be sulfated areprotected with an acyl protective group, for example, as acetates(R═CH₃) or benzoates (R=aryl) (Stages 1 and 2) All of the hydroxylgroups that are to remain as such are protected with benzyl group asbenzyl ethers (Stage 3). The amino group, which is subsequentlysulfonated, is masked as an azide (N₃) moiety (Stage 4). R¹ and R² aretypically sodium in the active pharmaceutical compound (e.g.,Fondaparinux sodium).

This strategy allows the final product to be prepared by following thesynthetic operations as outlined below:

a) Treatment of the late-stage intermediate with base to hydrolyze(deprotect) the acyl ester groups to reveal the five hydroxyl groups.The two R¹ and R² ester groups are hydrolyzed in this step as well.

b) Sulfonation of the newly revealed hydroxyl groups.

c) Hydrogenation of the O-sulfated pentasaccharide to de-benzylate thefive benzyl-protected hydroxyls, and at the same time, unmask the threeazides to the corresponding amino groups.

d) On the last step of the operation, the amino groups are sulfatedselectively at a high pH, in the presence of the five free hydroxyls togive Fondaparinux (FIG. 1).

While the above strategy has been shown to be viable, it is not withoutmajor drawbacks. One drawback lies in the procedure leading to the fullyprotected pentasaccharide (late stage intermediate), especially duringthe coupling of the D-glucuronic acid to the next adjacent glucose ring(the D-monomer to C-monomer in the EDCBA nomenclature shown in FIG. 1).Sugar oligomers or oligosaccharides, such as Fondaparinux, are assembledusing coupling reactions, also known as glycosylation reactions, to“link” sugar monomers together. The difficulty of this linking steparises because of the required stereochemical relationship between theD-sugar and the C-sugar, as shown in FIG. 2.

The stereochemical arrangement illustrated in FIG. 2 is described ashaving a β-configuration at the anomeric carbon of the D-sugar (denotedby the arrow). The linkage between the D and C units in Fondaparinux hasthis specific stereochemistry. There are, however, competing β- andα-glycosylation reactions.

The difficulties of the glycosylation reaction in the synthesis ofFondaparinux is well known. In 1991 Sanofi reported a preparation of adisaccharide intermediate in 51% yield having a 12/1 ratio of β/αstereochemistry at the anomeric position (Duchaussoy et al., Bioorg. &Med. Chem. Lett., 1(2), 99-102, 1991). In another publication (Sinay etal., Carbohydrate Research, 132, C5-C9, 1984) yields on the order of 50%with coupling times on the order of 6-days are reported. U.S. Pat. No.4,818,816 (see e.g., column 31, lines 50-56) discloses a 50% yield forthe β-glycosylation.

Alchemia's U.S. Pat. No. 7,541,445 is even less specific as to thedetails of the synthesis of this late-stage Fondaparinux syntheticintermediate. The '445 patent discloses several strategies for theassembly of the pentasaccharide (1+4, 3+2 or 2+3) using a 2-acylatedD-sugar (specifically 2-allyloxycarbonyl) for the glycosylation couplingreactions. However, Alchemia's strategy involves late-stagepentasaccharides that all incorporate a 2-benzylated D-sugar. Thetransformation of acyl to benzyl is performed either under acidic orbasic conditions. Furthermore, these transformations, using benzylbromide or benzyl trichloroacetimidate, typically result in extensivedecomposition and the procedure suffers from poor yields. Thus, suchtransformations (at a disaccharide, trisaccharide, and pentasaccharidelevel) are typically not acceptable for industrial scale production.

Examples of fully protected pentasaccharides are described in Duchaussoyet al., Bioorg. Med. Chem. Lett., 1 (2), 99-102, 1991; Petitou et al.,Carbohydr. Res., 167, 67-75, 1987; Sinay et al., Carbohydr. Res., 132,C5-C9, 1984; Petitou et al., Carbohydr. Res., 1147, 221-236, 1986; Leiet al., Bioorg. Med. Chem., 6, 1337-1346, 1998; Ichikawa et al., Tet.Lett., 27(5), 611-614, 1986; Kovensky et al., Bioorg. Med. Chem., 1999,7, 1567-1580, 1999. These fully protected pentasaccharides may beconverted to the O- and N-sulfated pentasaccharides using the four steps(described earlier) of: a) saponification with LiOH/H₂O₂/NaOH, b)O-sulfation by an Et₃N—SO₃ complex; c) de-benzylation and azidereduction via H₂/Pd hydrogenation; and d) N-sulfation with apyridine-SO₃ complex.

Even though many diverse analogs of the fully protected pentasaccharidehave been prepared, none use any protective group at the 2-position ofthe D unit other than a benzyl group. Furthermore, none of the fullyprotected pentasaccharide analogs offer a practical, scaleable andeconomical method for re-introduction of the benzyl moiety at the2-position of the D unit after removal of any participating group thatpromotes β-glycosylation.

Furthermore, the coupling of benzyl protected sugars proves to be asluggish, low yielding and problematic process, typically resulting insubstantial decomposition of the pentasaccharide (prepared over 50synthetic steps), thus making it unsuitable for a large [kilogram] scaleproduction process.

It has been a general strategy for carbohydrate chemists to usebase-labile ester-protecting group at 2-position of the D unit to buildan efficient and stereoselective β-glycosidic linkage. To construct theβ-linkage carbohydrate chemists have previously acetate and benzoateester groups, as described, for example, in the review by Poletti etal., Eur. J. Chem., 2999-3024, 2003.

The ester group at the 2-position of D needs to be differentiated fromthe acetate and benzoates at other positions in the pentasaccharide.These ester groups are hydrolyzed and sulfated later in the process and,unlike these ester groups, the 2-hydroxyl group of the D unit needs toremain as the hydroxyl group in the final product, Fondaparinux sodium.

Some of the current ester choices for the synthetic chemists in thefield include methyl chloro acetyl and chloro methyl acetate [MCA orCMA]. The mild procedures for the selective removal of theses groups inthe presence of acetates and benzoates makes them ideal candidates.However, MCA/CMA groups have been shown to produce unwanted and seriousside products during the glycosylation and therefore have not beenfavored in the synthesis of Fondaparinux sodium and its analogs. Forby-product formation observed in acetate derivatives see Seeberger etal., J. Org. Chem., 2004, 69, 4081-93. Similar by-product formation isalso observed using chloroacetate derivatives. See Orgueira et al., Eur.J. Chem., 9(1), 140-169, 2003.

Therefore, as will be appreciated, there are several limitations tocurrent processes used for the synthesis of fondaparinux sodium. Thus,there is a need in the art for new synthetic procedures that producefondaparinux and related compounds in high yield and with highstereoselectivity. The processes of the present invention address thelimitations known in the art and provide a unique, reliable and scalablesynthesis of compounds such as Fondaparinux sodium.

Additional advantages will be set forth in part in the description thatfollows, and in part will be obvious from the description, or may belearned by practice of the aspects described below. The advantagesdescribed below will be realized and attained by means of the elementsand combinations particularly pointed out in the appended claims. It isto be understood that both the foregoing general description and thefollowing detailed description are exemplary and explanatory only andare not restrictive.

SUMMARY OF THE INVENTION

Applicants have surprisingly found that in the synthesis ofFondaparinux, the use of a unique levulinate-protected 2-glucuronicacid-anhydro sugar coupling methodology allows for a highly efficientglycosylation reaction, thereby providing late stage intermediates oroligosaccharides (and Fondaparinux related oligomers) in high yield andin high β/α ratios. In particular, glycosylation of the2-levulinate-protected glucuronic acid can occur with high couplingyields (>65%) of the β-isomer, rapidly (for example, in an hour reactiontime), and with no detectable α-isomer upon column chromatographypurification. The levulinate protecting group may be efficiently andselectively removed from the glycosylated product in the presence ofpotential competing moieties (such as two acetate and two benzoategroups) to generate a free 2-hydroxyl group. The newly generatedhydroxyl group may be efficiently and quantitatively re-protected with atetrahydropyran (THP) group to provide a fully protected 2-THPcontaining pentasaccharide that may be selectively and consequentiallyO-sulfated, hydrogenated and N-sulfated to produce the desiredpentasaccharide, such as Fondaparinux, in excellent yields. Theinventors have surprisingly found that the THP group remains intact andprotected through all of the subsequent operations and is efficientlyremoved during work-up, after the final N-sulfonation step.

The present invention includes certain intermediate compounds identifiedbelow, including those of Formula I.

One embodiment of the invention is a process for making Fonadparinuxsodium by converting at least one compound selected from

where R₂ is Ac or Bz,

where R₂ is Ac or Bz,

where R₂ is Ac or Bz,

to Fonadaparinux sodium.

Yet another embodiment is a method of preparing an oligosaccharidehaving a β-glucosamine glycosidic linkage by reacting a 1,6-anhydroglucopyranosyl acceptor (e.g., 1,6-anhydro-β-D-glucopyranose) having anazide functional group at C2 and a hydroxyl group at C4 with a uronicacid glycopyranosyl donor having an activated anomeric carbon, alevulinate group at C2, and a protected acid group at C5 to form anoligosaccharide having a β-glycosidic linkage between the hydroxyl groupof the glucopyranosyl acceptor and the anomeric carbon of theglycopyranosyl donor.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts the structure of Fondaparinux sodium.

FIG. 2 depicts the stereochemical relationship between the D-sugar andthe C-sugar in Fondaparinux sodium.

FIG. 3 is a ¹H NMR spectrum of the EDC trimer.

FIG. 4 is a ¹H NMR spectrum of the EDC-1 trimer.

FIG. 5 is a ¹H NMR spectrum of the EDC-2 trimer.

FIG. 6 is a ¹H NMR spectrum of the EDC-3 trimer.

FIG. 7 is a ¹H NMR spectrum of the EDCBA-1 pentamer.

FIG. 8 is a ¹H NMR spectrum of the EDCBA-2 pentamer.

FIG. 9 is a ¹H NMR spectrum of the EDCBA pentamer.

FIG. 10 is a ¹H NMR spectrum of API-2 pentamer.

FIG. 11 is a ¹H NMR spectrum of API-3 pentamer.

DETAILED DESCRIPTION OF THE INVENTION

Applicants have surprisingly found that in the synthesis ofFondaparinux, the use of a unique levulinate-protected 2-glucuronicacid—anhydro sugar coupling methodology allows for an highly efficientglycosylation reaction, thereby providing late stage intermediates oroligosaccharides (and Fondaparinux related oligomers) in high yield andin high β/α ratios. In particular, glycosylation of the2-levulinate-protected glucuronic acid with an anhydro sugar occursquickly (for example, with a reaction time of about an hour), with highcoupling yields (>65%) of the β-isomer, and with high selectivity (forexample, with no detectable α-isomer upon column chromatographypurification). The levulinate protecting group may be efficiently andselectively removed from the glycosylated product in the presence ofpotential competing moieties (such as two acetate and two benzoategroups) to generate a free 2-hydroxyl group. The newly generatedhydroxyl group may be efficiently and quantitatively re-protected with atetrahydropyran (THP) group to provide a fully protected 2-THPcontaining pentasaccharide that may be selectively and consequentiallyO-Sulfated, hydrogenated and N-sulfated to produce the desiredpentasaccharide, such as Fondaparinux, in excellent yields. The THPgroup remains intact and protected through all of the subsequentoperations and is efficiently removed during work-up, after the finalN-sulfonation step.

The levulinyl group can be rapidly and almost quantitatively removed bytreatment with hydrazine hydrate as the deprotection reagent asillustrated in the example below. Under the same reaction conditionsprimary and secondary acetate and benzoate esters are hardly affected byhydrazine hydrate. See, e.g., Seeberger et al., J. Org. Chem., 69,4081-4093, 2004.

The syntheses of Fondaparinux sodium described herein takes advantage ofthe levulinyl group in efficient construction of the trisaccharide EDCwith improved β-selectivity for the coupling under milder conditions andincreased yields.

Substitution of the benzyl protecting group with a THP moiety providesits enhanced ability to be incorporated quantitatively in position-2 ofthe unit D of the pentasaccharide. Also, the THP group behaves in asimilar manner to a benzyl ether in terms of function and stability. Inthe processes described herein, the THP group is incorporated at the2-position of the D unit at this late stage of the synthesis (i.e.,after the D and C units have been coupled through a 1,2-trans glycosidic(β-) linkage). The THP protective group typically does not promote anefficient β-glycosylation and therefore is preferably incorporated inthe molecule after the construction of the β-linkage.

The scheme below exemplifies some of the processes of the presentinvention disclosed herein.

The tetrahydropyranyl (THP) protective group and the benzyl etherprotective group are suitable hydroxylprotective groups and can survivethe last four synthetic steps (described above) in the synthesis ofFondaparinux sodium, even under harsh reaction conditions. Certain otherprotecting groups do not survive the last four synthetic steps in highyield.

Thus, in one aspect, the present invention relates to novel levulinyland tetrahydropyran pentasaccharides. Such compounds are useful asintermediates in the synthesis of Fondaparinux.

In one embodiment, the present invention relates to a compound ofFormula I:

wherein

R₁ is levulinyl (Lev) or tetrahydropyran (THP);

R₂ is —O⁻ or a salt thereof, —OH, —OAcyl, or —OSO₃ ⁻ or a salt thereof;

R₃ is H, benzyl or a protecting group removable by hydrogenation (ahydroxyl protecting group) (for example, —CO₂ ⁻ or a salt thereof);

R₄ is N₃ (azide), NH₂, NH-protecting group (i.e., —NH—R where R is anamino protecting group), or NHSO₃ ⁻ or a salt thereof (e.g., NHSO₃Na,NHSO₃Li, NHSO₃K, and NHSO₃NH₄);

R₅ is C₁-C₆ alkyl; and

R₆ and R₇ are independently selected from —CO₂ ⁻ or a salt thereof,—CO₂H, and —CO₂R_(x) (where R_(x) is a C₁-C₆ alkyl, aryl, C₁-C₄alkoxy(aryl), aryl(C₁-C₆ alkyl), or C₁-C₄ alkoxy(aryl)(C₁-C₆ alkyl))(e.g., —CO₂Me, —CO₂CH₂C₆H₅ and —CO₂CH₂C₆H₄OMe); and

wherein said compound has alpha (α) stereochemistry at the carbonbearing the —OR₅ group.

In one embodiment, R₂ is —O-Acetyl or —O-Benzoyl. In another embodiment,R₂ is —O⁻, —ONa, —OLi, —OK or —OCs. In a further embodiment, R₂ is —OSO₃⁻, —OSO₃Na, —OSO₃Li, —OSO₃K or —OSO₃Cs.

In another embodiment, R₅ is methyl.

In a further embodiment, R₃ is benzyl or p-methoxybenzyl. In yet afurther embodiment, R₃ is —CO₂ ⁻, —CO₂Na, —CO₂Li, —CO₂K or —CO₂Cs.

In one embodiment of the compound of Formula (I), R₁ is levulinyl (Lev),R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃ (azide), R₅ ismethyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me.

In another embodiment of the compound of Formula (I), R₁ istetrahydropyran (THP), R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ isN₃ (azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me.

In yet another embodiment of the compound of Formula (I), R₁ istetrahydropyran (THP), R₂ is —O⁻ or a salt thereof, R₃ is benzyl, R₄ isN₃ (azide), R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or a salt thereof.

In a further embodiment of the compound of Formula (I), R₁ istetrahydropyran (THP), R₂ is —OSO₃ ⁻ or a salt thereof, R₃ is benzyl, R₄is N₃ (azide), R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or a salt thereof.

In another embodiment of the compound of Formula (I), R₁ istetrahydropyran (THP), R₂ is —OSO₃ ⁻ or a salt thereof, R₃ is H, R₄ isNH₂, R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or a salt thereof.

In another embodiment of the compound of Formula (I), R₁ istetrahydropyran (THP), R₂ is —OSO₃Na, R₃ is H, R₄ is NHSO₃Na, R₅ ismethyl, and R₆ and R₇ are —CO₂Na.

In yet a further embodiment, the present invention relates to a compoundof Formula I:

wherein R₁ is H, R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃(azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me.

Synthetic Processes

In another aspect, the present invention relates to processes for thepreparation of fondaparinux. The invention also relates to processes forthe preparation of novel intermediates useful in the synthesis offondaparinux. The processes described herein proceed in an efficientmanner, thereby providing the desired compounds in good yield and in amanner that is scalable and reproducible on an industrial scale.

Selective Coupling Strategy

The present invention provides a procedure for the selective formationof a β-anomer product from a glycosylation coupling reaction. Withoutwishing to be bound by theory, the applicants believe that the β/α ratioobserved during the processes described herein is due to thelevulinate-directed glycosylation exemplified below:

The 2-levulinate-mediated glycosylation reactions described hereinprovide a surprisingly high β/α ratio of coupled products. In thepresent invention, a high β-selectivity is obtained when the present,conformationally restricted, anhydro acceptor C is used. The highβ-selectivity is unexpected and may be due the conformationally lockedanhydroglucose.

Thus, in certain aspects, the present invention provides a levulinateester/tetrandropyranyl ether (Lev/THP) strategy for the protection,deprotection and re-protection of the 2-position of a glucuronicsaccharide, which is useful for the synthesis of Fondaparinux andrelated compounds.

In one embodiment, the present invention relates to a process forpreparing fondaparinux sodium:

In certain embodiments, the process includes (a) at least one of:

(i) deprotecting and then THP protecting a levulinate pentamer of theformula:

where R₂ is Ac or Bz to obtain a THP pentamer of the formula:

(ii) hydrolyzing a THP pentamer of the formula:

where R₂ is Ac or Bz to obtain a hydrolyzed pentamer of the formula:

(iii) sulfating a hydrolyzed pentamer of the formula:

to obtain an O-sulfated pentamer of the formula:

(iv) hydrogenating an O-sulfated pentamer of the formula:

to obtain a hydrogenated pentamer of the formula:

and

(vi) N-sulfating a hydrogenated pentamer of the formula:

to obtain Fondaparinux-THP of the formula:

and(b) optionally, converting the product of step (a) to Fondaparinuxsodium. For instance, the Fondaparinux-THP intermediate shown above canbe deprotected (i.e., the THP protecting group can be removed) to obtainFondaparinux.

In another aspect, the present invention relates to a process forpreparing a compound of Formula I:

wherein R₁ is H, R₂ is —OSO₃Na, R₃ is H, R₄ is NHSO₃Na, R₅ is methyl,and R₆ and R₇ are —CO₂Na, the process including:

(a) deprotecting a compound of Formula I wherein R₁ is levulinyl (Lev),R₂ is —OAcetyl or −Obenzoyl, R₃ is benzyl, R₄ is N₃ (azide), R₅ ismethyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me, to provide a compound ofFormula I wherein R₁ is H, R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄is N₃ (azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me;

(b) protecting the product of step (a) to provide a compound of FormulaI wherein R₁ is tetrahydropyran (THP), R₂ is —OAcetyl or —OBenzoyl, R₃is benzyl, R₄ is N₃ (azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is—CO₂Me;

(c) hydrolyzing the product of step (b) to provide a compound of FormulaI wherein R₁ is tetrahydropyran (THP), R₂ is —O⁻ or a salt thereof, R₃is benzyl, R₄ is N₃ (azide), R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or asalt thereof;

(d) sulfating the product of step (c) to provide a compound of Formula Iwherein R₁ is tetrahydropyran (THP), R₂ is —OSO₃ ⁻ or a salt thereof, R₃is benzyl, R₄ is N₃ (azide), R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or asalt thereof;

(e) hydrogenating the product of step (d) to provide a compound ofFormula I wherein R₁ is tetrahydropyran (THP), R₂ is —OSO₃ ⁻ or a saltthereof, R₃ is H, R₄ is NH₂, R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or asalt thereof;

(f) sulfating the product of step (e) to provide a compound of Formula Iwherein R₁ is tetrahydropyran (THP), R₂ is —OSO₃Na, R₃ is H, R₄ isNHSO₃Na, R₅ is methyl, and R₆ and R₇ are —CO₂Na; and

(g) deprotecting the product of step (f) to provide a compound ofFormula I wherein R₁ is H, R₂ is —OSO₃Na, R₃ is H, R₄ is NHSO₃Na, R₅ ismethyl, and R₆ and R₇ are —CO₂Na.

In one embodiment, deprotecting step (a) includes treatment with areagent selected from hydrazine, hydrazine hydrate, hydrazine acetateand R₈NH—NH₂ where R₈ is aryl, heteroaryl or alkyl.

In one embodiment, deprotecting step (a) includes treatment withhydrazine

In another embodiment, protecting step (b) includes treatment withdihyropyran or a dihydropyran derivative and an acid selected fromcamphor sulfonic acid (CSA), hydrochloric acid (HCl), p-toluenesulfonicacid (pTsOH) and Lewis acids.

In one embodiment protecting step (b) includes treatment withdihyropyran and an acid selected from hydrochloric acid andp-toluenesulfonic acid.

In another aspect, the present invention relates to a process forpreparing a THP pentamer of the formula:

wherein R₂ is Ac or Bz;the process including deprotecting and then THP protecting a compound ofthe formula:

In a further embodiment of this aspect, the process further includeshydrolyzing the THP pentamer to produce a hydrolyzed pentamer of theformula:

In a further embodiment of this aspect, the process further includessulfating the hydrolyzed pentamer to obtain an O-sulfated pentamer ofthe formula:

In a further embodiment of this aspect, the process further includeshydrogenating the O-sulfated pentamer to obtain a hydrogenated pentamerof the formula:

In a further embodiment of this aspect, the process further includesN-sulfating the hydrogenated pentamer to obtain fondaparinux-THP of theformula:

In a further embodiment of this aspect, the process further includesconverting the Fondaparinux-THP to Fondaparinux sodium. In oneembodiment, the conversion includes deprotecting the Fondaparinux-THP.

In another aspect, the present invention relates to a process forpreparing a compound of Formula I:

wherein R₁ is levulinyl (Lev), R₂ is —OAcetyl or —OBenzoyl, R₃ isbenzyl, R₄ is N₃ (azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is—CO₂Me;

the process including linking a compound of Formula EDC

wherein R₁ is levulinyl (Lev), R₂ is —OAcetyl or —OBenzoyl, R₃ isbenzyl, R₄ is N₃ (azide) and R₆ is —CO₂CH₂C₆H₅;

with a compound of Formula BA

wherein R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃ (azide), R₅is methyl and R₇ is —CO₂Me.

In one embodiment of this aspect, the process further includesconverting the resulting product to fondaparinux sodium.

In yet another aspect, the present invention relates to a process forpreparing a compound of Formula I:

wherein

R₁ is H, levulinyl (Lev) or tetrahydropyran (THP);

R₂ is —O⁻ or a salt thereof, —OH, —OAcyl, or —OSO₃ ⁻ or a salt thereof;

R₃ is H, benzyl or a protecting group removable by hydrogenation;

R₄ is N₃ (azide), NH₂, NH-protecting group (i.e., —NH—R where R is anamino protecting group), or NHSO₃ ⁻ or a salt thereof (e.g., NHSO₃Na,NHSO₃Li, NHSO₃K, and NHSO₃NH₄);

R₅ is C₁-C₆ alkyl; and

R₆ and R₇ are independently selected from —CO₂ ⁻ or a salt thereof,—CO₂H, and —CO₂R_(x) (where R_(x) is a C₁-C₆ alkyl, aryl, C₁-C₄alkoxy(aryl), aryl(C₁-C₆ alkyl), or C₁-C₄ alkoxy(aryl)(C₁-C₆ alkyl))(e.g., —CO₂Me, —CO₂CH₂C₆H₅ and —CO₂CH₂C₆H₄OMe); and

wherein said compound has alpha (α) stereochemistry at the carbonbearing the —OR₅ group;said process including linking a compound of Formula II:

wherein,

R₁ is H, levulinyl (Lev) or tetrahydropyran (THP);

R₂ is —O⁻ or a salt thereof, —OH, —OAcyl, —OSO₃ ⁻ or a salt thereof;

R₃ is H, benzyl or a protecting group removable by hydrogenation;

R₄ is N₃ (azide), NH₂, NH-protecting group (i.e., —NH—R where R is anamino protecting group), or NHSO₃ ⁻ or a salt thereof (e.g., NHSO₃Na,NHSO₃Li, NHSO₃K, and NHSO₃NH₄);

R₆ and R₇ are independently selected from —CO₂ ⁻ or a salt thereof,—CO₂H, and —CO₂R_(x) (where R_(x) is a C₁-C₆ alkyl, aryl, C₁-C₄alkoxy(aryl), aryl(C₁-C₆ alkyl), or C₁-C₄ alkoxy(aryl)(C₁-C₆ alkyl))(e.g., —CO₂Me, —CO₂CH₂C₆H₅ and —CO₂CH₂C₆H₄OMe); and

R₉ is R₁ or R₂,

with a compound of Formula III

wherein

R₂ is —O⁻ or a salt thereof, —OH, —OAcyl, —OSO₃ ⁻ or a salt thereof;

R₃ is H, benzyl or a protecting group removable by hydrogenation;

R₄ is N₃ (azide), NH₂, NH-protecting group (i.e., —NH—R where R is anamino protecting group), or NHSO₃ ⁻ or a salt thereof (e.g., NHSO₃Na,NHSO₃Li, NHSO₃K, and NHSO₃NH₄);

R₅ is C₁-C₆ alkyl.

In certain embodiments of this aspect, the compound of Formula II is

and the compound of Formula III is

In yet another aspect, the present invention relates to a process forpreparing a compound of Formula I:

wherein,

R₁ is H, levulinyl (Lev) or tetrahydropyran (THP);

R₂ is —O⁻ or a salt thereof, —OH, —OAcyl, or —OSO₃ ⁻ or a salt thereof;

R₃ is H, benzyl or a protecting group removable by hydrogenation;

R₄ is N₃ (azide), NH₂, NH-protecting group (i.e., —NH—R where R is anamino protecting group), or NHSO₃ ⁻ or a salt thereof (e.g., NHSO₃Na,NHSO₃Li, NHSO₃K, and NHSO₃NH₄);

R₅ is C₁-C₆ alkyl; and

R₆ and R₇ are independently selected from —CO₂ ⁻ or a salt thereof,—CO₂H, and —CO₂R_(x) (where R_(x) is a C₁-C₆ alkyl, aryl, C₁-C₄alkoxy(aryl), aryl(C₁-C₆ alkyl), or C₁-C₄ alkoxy(aryl)(C₁-C₆ alkyl))(e.g., —CO₂Me, —CO₂CH₂C₆H₅ and —CO₂CH₂C₆H₄OMe); and

wherein said compound has alpha (α) stereochemistry at the carbonbearing the —OR₅ group;the process including linking a compound of Formula IV:

wherein,

R₁ is H, levulinyl (Lev) or tetrahydropyran (THP);

R₂ is —O⁻ or a salt thereof, —OH, —OAcyl, —OSO₃ ⁻ or a salt thereof;

R₃ is H, benzyl or a protecting group removable by hydrogenation;

R₄ is N₃ (azide), NH₂, NH-protecting group (i.e., —NH—R where R is anamino protecting group), or NHSO₃ ⁻ or a salt thereof (e.g., NHSO₃Na,NHSO₃Li, NHSO₃K, and NHSO₃NH₄); and

R₆ is selected from —CO₂ ⁻ or a salt thereof, —CO₂H, and —CO₂R_(x)(where R_(x) is a C₁-C₆ alkyl, aryl, C₁-C₄ alkoxy(aryl), aryl(C₁-C₆alkyl), or C₁-C₄ alkoxy(aryl)(C₁-C₆ alkyl)) (e.g., —CO₂Me, —CO₂CH₂C₆H₅and —CO₂CH₂C₆H₄OMe),

with a compound of Formula V:

wherein,

R₁ is H, levulinyl (Lev) or tetrahydropyran (THP);

R₂ is —O⁻ or a salt thereof, —OH, —OAcyl, —OSO₃ ⁻ or a salt thereof;

R₃ is H, benzyl or a protecting group removable by hydrogenation;

R₄ is N₃ (azide), NH₂, NH-protecting group (i.e., —NH—R where R is anamino protecting group), or NHSO₃ ⁻ or a salt thereof (e.g., NHSO₃Na,NHSO₃Li, NHSO₃K, and NHSO₃NH₄);

R₅ is C₁-C₆ alkyl; and

R₇ is selected from —CO₂ ⁻ or a salt thereof, —CO₂H, and —CO₂R_(x)(where R_(x) is a C₁-C₆ alkyl, aryl, C₁-C₄ alkoxy(aryl), aryl(C₁-C₆alkyl), or C₁-C₄ alkoxy(aryl)(C₁-C₆ alkyl)) (e.g., —CO₂Me, —CO₂CH₂C₆H₅and —CO₂CH₂C₆H₄OMe); and

R₉ is R₁ or R₂.

In certain embodiments of this aspect, the compound of Formula IV is

and the compound of Formula V is

In another aspect, the present invention relates to a process forpreparing a compound of Formula I wherein R₁ is tetrahydropyran (THP),R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃ (azide), R₅ ismethyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me, the process including:

(a) deprotecting a compound of Formula I wherein R₁ is levulinyl (Lev),R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃ (azide), R₅ ismethyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me to afford a compound ofFormula I wherein R₁ is H, R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄is N₃ (azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅, and R₇ is —CO₂Me; and

(b) THP protecting the product of step (a).

In one embodiment, deprotecting step (a) includes treatment with areagent selected from hydrazine, hydrazine hydrate, hydrazine acetateand R₈NH—NH₂ where R₈ is aryl, heteroaryl or alkyl. In one embodimentdeprotecting step (a) comprises treatment with hydrazine.

In one embodiment, protecting step (b) comprises treatment withdihyropyran or a dihydropyran derivative and an acid selected fromcamphor sulfonic acid (CSA), hydrochloric acid (HCl), p-toluenesulfonicacid (pTsOH) and Lewis acids. In one embodiment, protecting step (b)comprises treatment with dihyropyran and an acid selected fromhydrochloric acid and p-toluenesulfonic acid.

In another aspect, the present invention relates to a process forpreparing a compound of Formula I wherein R₁ is tetrahydropyran (THP),R₂ is —O⁻ or a salt thereof, R₃ is benzyl, R₄ is N₃ (azide), R₅ ismethyl, and R₆ and R₇ are —CO₂ ⁻ or a salt thereof, comprisinghydrolyzing a compound of Formula I wherein R₁ is tetrahydropyran (THP),R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃ (azide), R₅ ismethyl, R₆ is —CO₂CH₂C₆H₅, and R₇ is —CO₂Me.

In another aspect, the present invention relates to a process forpreparing a compound of Formula I wherein R₁ is tetrahydropyran (THP),R₂ is —OSO₃ ⁻ or a salt thereof, R₃ is benzyl, R₄ is N₃ (azide), R₅ ismethyl, and R₆ and R₇ are —CO₂ ⁻ or a salt thereof, comprising sulfatinga compound of Formula I wherein R₁ is tetrahydropyran (THP), R₂ is —O⁻or a salt thereof, R₃ is benzyl, R₄ is N₃ (azide), R₅ is methyl, and R₆and R₇ are —CO₂ ⁻ or a salt thereof.

In another aspect, the present invention relates to a process forpreparing a compound of Formula I wherein R₁ is tetrahydropyran (THP),R₂ is —OSO₃ ⁻ or a salt thereof, R₃ is H, R₄ is NH₂, R₅ is methyl, andR₆ and R₇ are —CO₂ ⁻ or a salt thereof, comprising the step ofhydrogenating a compound of Formula I wherein R₁ is tetrahydropyran(THP), R₂ is —OSO₃ ⁻ or a salt thereof, R₃ is benzyl, R₄ is N₃ (azide),R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or a salt thereof.

In another aspect, the present invention relates to a process forpreparing a compound of Formula I wherein R₁ is tetrahydropyran (THP),R₂ is —OSO₃Na, R₃ is H, R₄ is NHSO₃Na, R₅ is methyl, and R₆ and R₇ are—CO₂Na, comprising the step of sulfating a compound of Formula I whereinR₁ is tetrahydropyran (THP), R₂ is —OSO₃ ⁻ or a salt thereof, R₃ is H,R₄ is NH₂, R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or a salt thereof.

In a further aspect, the present invention relates to a process formaking a compound of Formula I:

wherein R₁ is H, R₂ is —OSO₃Na, R₃ is H, R₄ is NHSO₃Na, R₅ is methyl,and R₆ and R₇ are —CO₂Na;

the process including deprotecting a compound of Formula I wherein R₁ istetrahydropyran (THP), R₂ is —OSO₃Na, R₃ is H, R₄ is NHSO₃Na, R₅ ismethyl, and R₆ and R₇ are —CO₂Na.

In yet a further aspect, the present invention relates to a process formaking a compound of Formula 8:

comprising reacting a compound of Formula 9:

with a compound of Formula 10:

Fondaparinux Sodium

In a further aspect, the present invention relates to Fondaparinux, or asalt thereof (e.g., Fondaparinux sodium) containing a compound selectedfrom P2, P3, P4, and combinations thereof.

Compound P2 (Methylated Nitrogen on the E Ring):

Compound P3 (Methylated Nitrogen on the A Ring):

Compound P4 (N-Formyl Group on the C Ring):

In additional embodiments, the present invention relates to acomposition (such as a pharmaceutical composition) that includesFondaparinux, or a salt thereof (e.g., Fondaparinux sodium) and acompound selected from P2, P3, P4, and combinations thereof.

In certain embodiments, the Fondaparinux, or a salt thereof (e.g.,Fondaparinux sodium), or composition contains at least 90, 95, 98, 99 or99.5% Fondaparinux, or salt thereof, based on the total weight ofFondaparinux or composition.

In certain embodiments, Compound P2 is present in an amount of greaterthan 0% and less than about 0.5%, such as greater than 0% and less thanabout 0.4%, greater than 0% and less than about 0.3%, greater than 0%and less than about 0.2% and greater than 0% and less than about 0.1%,based on the total weight of Fondaparinux or composition.

In certain embodiments, Compound P3 is present in an amount of greaterthan 0% and less than about 0.5%, such as greater than 0% and less thanabout 0.4%, greater than 0% and less than about 0.3%, greater than 0%and less than about 0.2% and greater than 0% and less than about 0.1%,based on the total weight of Fondaparinux or composition.

In certain embodiments, Compound P4 is present in an amount of greaterthan 0% and less than about 0.5%, such as greater than 0% and less thanabout 0.4%, greater than 0% and less than about 0.3%, greater than 0%and less than about 0.2% and greater than 0% and less than about 0.1%,based on the total weight of Fondaparinux or composition.

In additional embodiments, the Fondaparinux, or a salt thereof (e.g.,Fondaparinux sodium) (or composition that includes Fondaparinux, or asalt thereof (e.g., Fondaparinux sodium)) may also contain Compound P1(in addition to containing a compound selected from P2, P3, P4, andcombinations thereof).

Compound P1 (Beta-Anomer of Fondaparinux Sodium)

In certain embodiments, Compound P1 is present in an amount of greaterthan 0% and less than about 0.5%, such as greater than 0% and less thanabout 0.4%, greater than 0% and less than about 0.3%, greater than 0%and less than about 0.2% and greater than 0% and less than about 0.1%,based on the total weight of Fondaparinux or composition.

In additional embodiments, the present invention relates to acomposition (such as a pharmaceutical composition) that includesFondaparinux or a salt thereof (e.g., Fondaparinux sodium) and one ormore tetrahydropyran protected pentasaccharides. In additionalembodiments, the tetrahydropyran protected pentasaccharide is any of thetetrahydropyran protected pentasaccharides as described in any of theembodiments herein.

In certain embodiments, the tetrahydropyran protected pentasaccharide ispresent in an amount of greater than 0% and less than about 0.5%, suchas greater than 0% and less than about 0.4%, greater than 0% and lessthan about 0.3%, greater than 0% and less than about 0.2%, greater than0% and less than about 0.1%, based on the total weight of Fondaparinuxor composition.

Any of the aforementioned forms of Fondaparinux (or a salt thereof) orcompositions containing Fondaparinux (or a salt thereof) may beadministered (e.g., 2.5 mg, 5 mg, 7.5 mg, 10 mg, solution for injection)for the prophylaxis of deep vein thrombosis (DVT) which may lead topulmonary embolism (PE) in patients undergoing (i) hip fracture surgery(including extended prophylaxis), (ii) hip replacement surgery, (iii)knee replacement surgery and (iv) abdominal surgery (who are at risk forthromboembolic complications). The forms and compositions describedherein may also be administered in conjunction with wafarin sodium forthe treatment of acute DVT and PE.

DEFINITIONS

Examples of alkyl groups having one to six carbon atoms, are methyl,ethyl, propyl, butyl, pentyl, hexyl, and all isomeric forms and straightand branched thereof.

The term “acyl” unless otherwise defined refers to the chemical group—C(O)R. R can be, for example, aryl (e.g., phenyl) or alkyl (e.g., C₁-C₆alkyl).

The term “aryl” refers to an aromatic group having 6 to 14 carbon atomssuch as, for example, phenyl, naphthyl, tetrahydronapthyl, indanyl, andbiphenyl. The term “heteroaryl” refers to an aromatic group having 5 to14 atoms where at least one of the carbons has been replaced by N, O orS. Suitable examples include, for example, pyridyl, quinolinyl,dihydroquinolinyl, isoquinolinyl, quinazolinyl, dihydroquinazolyl, andtetrahydroquinazolyl.

It will be apparent to those skilled in the art that sensitivefunctional groups may need to be protected and deprotected duringsynthesis of a compound of the invention. This may be achieved byconventional methods, for example as described in “Protective Groups inOrganic Synthesis” by Greene and Wuts, John Wiley & Sons Inc (1999), andreferences therein which can be added or removed using the proceduresset forth therein. Examples of protected hydroxyl groups (i.e., hydroxylprotecting groups) include silyl ethers such as those obtained byreaction of a hydroxyl group with a reagent such as, but not limited to,t-butyldimethyl-chlorosilane, trimethylchlorosilane,triisopropylchlorosilane, triethylchlorosilane; substituted methyl andethyl ethers such as, but not limited to, methoxymethyl ether,methylhiomethyl ether, benzyloxymethyl ether, t-butoxymethyl ether,2-methoxyethoxymethyl ether, tetrahydropyranyl ethers, 1-ethoxyethylether, allyl ether, benzyl ether; esters such as, but not limited to,benzoylformate, formate, acetate, trichloroacetate, and trifluoracetate.Examples of protected amine groups (i.e., amino protecting groups)include, but are not limited to, amides such as, formamide, acetamide,trifluoroacetamide, and benzamide; imides, such as phthalimide, anddithiosuccinimide; and others. Examples of protected sulfhydryl groupsinclude, but are not limited to, thioethers such as S-benzyl thioether,and S-4-picolyl thioether; substituted S-methyl derivatives such ashemithio, dithio and aminothio acetals; and the like.

A protecting group that can be removed by hydrogenation is, by way ofexample, benzyl or a substituted benzyl group, for example benzylethers, benzylidene acetals. While the benzyl group itself is a commonlyused protecting group that can be removed by hydrogenation, one exampleof a substituted benzyl protecting group is p-methoxy benzyl.

A number of hydrazine and hydrazine derivative are available for thedeprotection (removal) of tetrahydropyran (THP) protecting group,including, but not limited to, hydrazine [NH₂—NH₂], hydrazine hydrate[NH₂—NH₂.H₂O] and hydrazine acetate [NH₂—NH₂.AcOH] and alkyl and arylhydrazine derivatives such as R₈NH—NH₂ where R₈ is aryl, heteroaryl oralkyl.

Lewis acids known in the art include, for example, magnesium chloride,aluminum chloride, zinc chloride, boron trifluoride dimethyl etherate,titanium(IV) chloride and ferric chloride.

Throughout the description and claims of this specification the word“comprise” and other forms of the word, such as “comprising” and“comprises,” means including but not limited to, and is not intended toexclude, for example, other additives, components, integers, or steps.

As used in the specification and the appended claims, the singular forms“a,” “an” and “the” include plural referents unless the context clearlydictates otherwise. Thus, for example, reference to “a component”includes mixtures of two or more components.

Ranges can be expressed herein as from “about” one particular value,and/or to “about” another particular value. When such a range isexpressed, another aspect includes from the one particular value and/orto the other particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another aspect. It will be furtherunderstood that the endpoints of each of the ranges are significant bothin relation to the other endpoint, and independently of the otherendpoint. It is also understood that there are a number of valuesdisclosed herein, and that each value is also herein disclosed as“about” that particular value in addition to the value itself. Forexample, if the value “10” is disclosed, then “about 10” is alsodisclosed. It is also understood that each unit between two particularunits are also disclosed. For example, if 10 and 15 are disclosed, then11, 12, 13, and 14 are also disclosed.

Throughout this specification, various publications are referenced. Thedisclosures of these publications in their entireties are herebyincorporated by reference into this application in order to more fullydescribe the state of the art to which the disclosed matter pertains.The references disclosed are also individually and specificallyincorporated by reference herein for the material contained in them thatis discussed in the sentence in which the reference is relied upon.

The following examples are merely illustrative of the present inventionand should not be construed as limiting the scope of the invention inany way as many variations and equivalents that are encompassed by thepresent invention will become apparent to those skilled in the art uponreading the present disclosure.

Examples

In the synthesis of Fondaparinux sodium, the monomers A2, B1, C, D and Edescribed herein may be made either by processes described in the artor, e.g., in the case of the D monomer, by a process as describedherein. The B1 and A2 monomers may then linked to form a disaccharide,BA dimer. The E, D and C monomers may be linked to form a trisaccharide,EDC trimer. The EDC trimer may be derivatized to form an intermediatesuitable for coupling with the BA dimer, thereby forming apentasaccharides (EDCBA) pentamer. The EDCBA pentamer is an intermediatethat may be converted through a series of reactions to Fondaparinuxsodium. This strategy described herein provides an efficient method formulti kilograms preparation of Fondaparinux in high yields and highstereoselectivity.

Synthetic Procedures

The following abbreviations are used herein: Ac is acetyl; ACN isacetonitrile; MS is molecular sieves; DMF is dimethyl formamide; PMB isp-methoxybenzyl; Bn is benzyl; DCM is dichloromethane; THF istetrahydrofuran; TFA is trifluoro acetic acid; CSA is camphor sulfonicacid; TEA is triethylamine; MeOH is methanol; DMAP isdimethylaminopyridine; RT is room temperature; CAN is ceric ammoniumnitrate; Ac₂O is acetic anhydride; HBr is hydrogen bromide; TEMPO istetramethylpiperidine-N-oxide; TBACl is tetrabutyl ammonium chloride;EtOAc is ethyl acetate; HOBT is hydroxybenzotriazole; DCC isdicyclohexylcarbodiimide; Lev is levunlinyl; TBDPS is tertiary-butyldiphenylsilyl; TCA is trichloroacetonitrile; O-TCA isO-trichloroacetimidate; Lev₂O is levulinic anhydride; DIPEA isdiisopropylethylamine; Bz is benzoyl; TBAF is tetrabutylammoniumfluoride; DBU is diazabicycloundecane; BF₃.Et₂O is boron trifluorideetherate; TMSI is trimethylsilyl iodide; TBAI is tetrabutylammoniumiodide; TES-Tf is triethylsilyl trifluoromethanesulfonate (triethylsilyltriflate); DHP is dihydropyran; PTS is p-toluenesulfonic acid.

The monomers used in the processes described herein may be prepared asdescribed in the art, or can be prepared using the methods describedherein.

The synthesis of Monomer A-2 (CAS Registry Number 134221-42-4) has beendescribed in the following references: Arndt et al., Organic Letters,5(22), 4179-4182, 2003; Sakairi et al., Bulletin of the Chemical Societyof Japan, 67(6), 1756-8, 1994; and Sakairi et al., Journal of theChemical Society, Chemical Communications, (5), 289-90, 1991, and thereferences cited therein, which are hereby incorporated by reference intheir entireties.

Monomer C(CAS Registry Number 87326-68-9) can be synthesized using themethods described in the following references: Ganguli et al.,Tetrahedron: Asymmetry, 16(2), 411-424, 2005; Izumi et al., Journal ofOrganic Chemistry, 62(4), 992-998, 1997; Van Boeckel et al., Recueil:Journal of the Royal Netherlands Chemical Society, 102(9), 415-16, 1983;Wessel et al., Helvetica Chimica Acta, 72(6), 1268-77, 1989; Petitou etal., U.S. Pat. No. 4,818,816 and references cited therein, which arehereby incorporated by reference in their entireties.

Monomer E (CAS Registry Number 55682-48-9) can be synthesized using themethods described in the following literature references: Hawley et al.,European Journal of Organic Chemistry, (12), 1925-1936, 2002; Dondoni etal., Journal of Organic Chemistry, 67(13), 4475-4486, 2002; Van derKlein et al., Tetrahedron, 48(22), 4649-58, 1992; Hori et al., Journalof Organic Chemistry, 54(6), 1346-53, 1989; Sakairi et al., Bulletin ofthe Chemical Society of Japan, 67(6), 1756-8, 1994; Tailler et al.,Journal of the Chemical Society, Perkin Transactions 1: Organic andBio-Organic Chemistry, (23), 3163-4, (1972-1999) (1992); Paulsen et al.,Chemische Berichte, 111(6), 2334-47, 1978; Dasgupta et al., Synthesis,(8), 626-8, 1988; Paulsen et al., Angewandte Chemie, 87(15), 547-8,1975; and references cited therein, which are hereby incorporated byreference in their entireties.

Monomer B-1 (CAS Registry Number 444118-44-9) can be synthesized usingthe methods described in the following literature references: Lohman etal., Journal of Organic Chemistry, 68(19), 7559-7561, 2003; Orgueira etal., Chemistry—A European Journal, 9(1), 140-169, 2003; Manabe et al.,Journal of the American Chemical Society, 128(33), 10666-10667, 2006;Orgueira et al., Angewandte Chemie, International Edition, 41(12),2128-2131, 2002; and references cited therein, which are herebyincorporated by reference in their entireties.

Synthesis of Monomer D

Monomer D was prepared in 8 synthetic steps from glucose pentaacetateusing the following procedure:

Pentaacetate SM-B was brominated at the anomeric carbon using HBr inacetic acid to give bromide derivative IntD1. This step was carried outusing the reactants SM-B, 33% hydrogen bromide, acetic acid anddichloromethane, stirring in an ice water bath for about 3 hours andevaporating at room temperature. IntD1 was reductively cyclized withsodium borohydride and tetrabutylammonium iodide in acetonitrile using 3Å molecular sieves as dehydrating agent and stirring at 40° C. for 16hours to give the acetal derivative, IntD2. The three acetyl groups inIntD2 were hydrolyzed by heating with sodium methoxide in methanol at50° C. for 3 hours and the reaction mixture was neutralized using Dowex50WX8-100 resin (Aldrich) in the acid form to give the trihydroxy acetalderivative IntD3.

The C4 and C6 hydroxyls of IntD3 were protected by mixing withbenzaldehyde dimethyl acetate and camphor sulphonic acid at 50° C. for 2hours to give the benzylidene-acetal derivative IntD4. The free hydroxylat the C3 position of IntD4 was deprotonated with sodium hydride in THFas solvent at 0° C. and alkylated with benzyl bromide in THF, andallowing the reaction mixture to warm to room temperature with stirringto give the benzyl ether IntD5. The benzylidene moiety of IntD5 wasdeprotected by adding trifluoroacetic acid in dichloromethane at 0° C.and allowing it to warm to room temperature for 16 hours to give IntD6with a primary hydroxyl group. IntD6 was then oxidized with TEMPO(2,2,6,6-tetramethyl-1-piperidine-N-oxide) in the presence oftetrabutylammonium chloride, sodium bromide, ethyl acetate, sodiumchlorate and sodium bicarbonate, with stirring at room temperature for16 hours to form the carboxylic acid derivative IntD7. The acid IntD7was esterified with benzyl alcohol and dicyclohexylcarbodiimide (otherreactants being hydroxybenzotriazole and triethylamine) with stirring atroom temperature for 16 hours to give Monomer D.

Synthesis of the BA Dimer

The BA Dimer was prepared in 12 synthetic steps from Monomer B1 andMonomer A2 using the following procedure:

The C4-hydroxyl of Monomer B-1 was levulinated using levulinic anhydrideand diisopropylethylamine (DIPEA) with mixing at room temperature for 16hours to give the levulinate ester BMod1, which was followed byhydrolysis of the acetonide with 90% trifluoroacetic acid and mixing atroom temperature for 4 hours to give the diol BMod2. The C1 hydroxyl ofthe diol BMod2 was silylated with tert-butyldiphenylsilylchloride bymixing at room temperature for 3 hours to give silyl derivative BMod3.The C2-hydroxyl was then benzoylated with benzoyl chloride in pyridine,and mixed at room temperature for 3 hours to give compound BMod4. Thesilyl group on BMod4 was then deprotected with tert-butyl ammoniumfluoride and mixing at room temperature for 3 hours to give theC1-hydroyl BMod5. The C1-hydroxyl is then allowed to react withtrichloroacetonitrile in the presence of diazobicycloundecane (DBU) andmixing at room temperature for 2 hours to give the trichloroacetamidate(TCA) derivative BMod6, which suitable for coupling, for example withMonomer A-2.

Monomer A-2 was prepared for coupling by opening the anhydro moiety withBF₃.Et₂O followed by acetylation of the resulting hydroxyl groups togive the triacetate derivative AMod1.

Monomer A2 was prepared for the coupling reaction by opening the anhydromoiety and acetylation of the resulting hydroxyl groups to give thetriacetate derivative AMod1. This transformation occurs using borontrifluoride etherate, acetic anhydride and dichloromethane, between −20°C. and room temperature for 3 hours. The C1-Acetate of AMod1 was thenhydrolyzed and methylated in two steps to give the diacetate AMod3. Thatis, first AMod1 was reacted with trimethylsilyl iodide and mixed at roomtemperature for 2 hours, then reacted with and tetrabutyl ammoniumiodide. This mixture was reacted with diisoproylethylamine and methanoland stirred for 16 hours at room temperature, thus forming AMod3. The C4and C6 acetates of AMod3 are hydrolyzed with sodium methoxide to givethe diol Amod4. The AMod3 mixture was also subjected to mixing at roomtemperature for 3 hours with Dowex 50 W×4×8-100 resin in the acid formfor neutralization. This formed Amod4. The C6-hydroxyl of AMod4 is thenbenzoylated by treating with benzoyl chloride in pyridine at −40° C. andthen allowing it to warm up to −10° C. over 2 hours to give AMod5.

Coupling of monomer AMod5 with the free C4-hydroxyl group of BMod6 wasperformed in the presence of BF₃.Et₂O and dichloromethane with mixingbetween −20° C. and room temperature for 3 hours to provide disaccharideBA1. The C4-levulinyl moiety of the disaccharide was then hydrolyzedwith hydrazine to give the BA Dimer, which is suitable for subsequentcoupling reactions.

Synthesis of EDC Trimer

The EDC Trimer was prepared in 10 synthetic steps from Monomer E,Monomer D and Monomer C using the following procedure:

Monomer E was prepared for coupling by opening the anhydro moiety withBF₃.Et₂O followed by acetylation of the resulting hydroxyl groups togive diacetate EMod1. This occurs by the addition of Monomer E withboron trifluoride etherate, acetic anhydride and dichloromethane at −10°C., and allowing the reaction to warm to room temperature with stirringfor 3 hours. The C1-Acetate of EMod1 is then hydrolyzed to give thealcohol, EMod2. This occurs by reacting Emod1 with hydrazine acetate anddimethylformamide and mixing at room temperature for 3 hours. TheC1-hydroxyl of Emod2 is then reacted with trichloroacetonitrile to givethe trichloro acetamidate (TCA) derivative EMod3 suitable for coupling,which reaction also employs diazabicycloundecane and dichloromethane andmixing at room temperature for 2 hours.

Monomer D, having a free C4-hydroxyl group, was coupled with monomerEMod3 in the presence of triethylsilyl triflate with mixing at −40° C.for 2 hours to give the disaccharide ED Dimer. The acetal on ring sugarD of the ED Dimer is hydrolyzed to give the C1,C2-diol ED1. This occursby reacting the ED Dimer with 90% trifluoro acetic acid and mixing atroom temperature for 4 hours. The C1-hydroxyl moiety of ED1 was thensilylated with tert-butyldiphenylsilyl chloride to give the silylderivative ED2. The C2-hydroxyl of ED2 was then allowed to react withlevulinic anhydride in the presence of dimethylaminopyridine (DMAP) anddiethylisopropylamine for approximately 16 hours to give the levulinateester ED3. The TBDPS moiety is then deprotected by removal withtert-butylammonium fluoride in acetic acid with mixing at roomtemperature for 3 hours to give ED4 having a C1-hydroxyl. TheC1-hydroxyl moiety of ED4 was then allowed to react withtrichloroacetonitrile to give the TCA derivative ED5, which is suitablefor coupling.

The C1-hydroxyl moiety of ED4 is then allowed to react withtrichloroacetonitrile to give the TCA derivative ED5 suitable forcoupling using diazabicycloundecane and dichloromethane, and mixing atroom temperature for 2 hours. Monomer C, having a free C4-hydroxylgroup, was then coupled with the disaccharide ED5 in the presence oftriethylsilyl triflate and mixed at −20° C. for 2 hours to give thetrisaccharide EDC Trimer.

Synthesis of the EDCBA Pentamer

The EDCBA Pentamer was prepared using the following procedure:

The preparation of EDCBA Pentamer is accomplished in two parts asfollows. In part 1, the EDC Trimer, a diacetate intermediate, isprepared for the coupling reaction with Dimer BA by initially openingthe anhydro moiety and acetylation of the resulting hydroxyl groups togive the tetraacetate derivative EDC1. This occurs by reacting the EDCTrimer with boron trifluoride etherate, acetic anhydride anddichlormethane and stirring between −10° C. and room temperature for 3hours. The C1-Acetate of EDC1 is then hydrolyzed to give the alcohol,EDC2, by reacting EDC1 with benzylamine [BnNH₂] and tetrahydrofuran andmixing at −10° C. for 3 hours. The C1-hydroxyl of EDC2 is then reactedwith trichloroacetonitrile and diazabicycloundecane, with mixing at roomtemperature for 2 hours, to give the trichloro acetamidate (TCA)derivative EDC3 suitable for coupling.

In Part 2 of the EDCBA Pentameter synthesis, the Dimer BA, having a freeC4-hydroxyl group, is coupled with trisaccharide EDC3 in the presence oftriethylsilyltriflate at −30° C. mixing for 2 hours to give thepentasaccharide EDCBA1. The levulinyl ester on C2 of sugar D in EDCBA1is hydrolyzed with a mixture of deprotecting agents, hydrazine hydrateand hydrazine acetate and stiffing at room temperature for 3 hours togive the C2-hydroxyl containing intermediate EDCBA2. The C2-hydroxylmoiety on sugar D of EDCBA2 is then alkylated with dihydropyran (DHP) inthe presence of camphor sulfonic acid (CSA) and tetrahydrofuran withmixing at room temperature for 3 hours to give the tetrahydropyranylether (THP) derivative, EDCBA Pentamer.

Synthesis of Fondaparinux

Fondaparinux was prepared using the following procedure:

The ester moieties in EDCBA Pentamer were hydrolyzed with sodium andlithium hydroxide in the presence of hydrogen peroxide in dioxane mixingat room temperature for 16 hours to give the pentasaccharideintermediate API1. The five hydroxyl moieties in API1 were sulfatedusing a pyridine-sulfur trioxide complex in dimethylformamide, mixing at60° C. for 2 hours and then purified using column chromatography(CG-161), to give the pentasulfated pentasaccharide API2. Theintermediate API2 was then hydrogenated to reduce the three azides onsugars E, C and A to amines and the reductive deprotection of the fivebenzyl ethers to their corresponding hydroxyl groups to form theintermediate API3. This transformation occurs by reacting API2 with 10%palladium/carbon catalyst with hydrogen gas for 72 hours. The threeamines on API3 were then sulfated using the pyridine-sulfur trioxidecomplex in sodium hydroxide and ammonium acetate, allowing the reactionto proceed for 12 hours. The acidic work-up procedure of the reactionremoves the THP group to provide crude fondaparinux which is purifiedand is subsequently converted to its salt form. The crude mixture waspurified using an ion-exchange chromatographic column (HiQ resin)followed by desalting using a size exclusion resin or gel filtration(Biorad Sephadex G25) to give the final API, fondaparinux sodium

Experimental Procedures Preparation of IntD1 Bromination of GlucosePentaacetate

To a 500 ml flask was added 50 g of glucose pentaacetate (C₆H₂₂O₁₁) and80 ml of methylene chloride. The mixture was stirred at ice-water bathfor 20 min HBr in HOAc (33%, 50 ml) was added to the reaction mixture.After stirring for 2.5 hr another 5 ml of HBr was added to the mixture.After another 30 min, the mixture was added 600 ml of methylenechloride. The organic mixture was washed with cold water (200 ml×2),Saturated NaHCO₃(200 ml×2), water (200 ml) and brine (200 ml×2). Theorganic layer was dried over Na₂SO₄ and the mixture was evaporated at RTto give white solid as final product, bromide derivative, IntD1 (˜95%yield). C₁₄H₁₉BrO₉, TLC R_(f)=0.49, SiO₂, 40% ethyl acetate/60% hexanes;Exact Mass 410.02.

Preparation of IntD2 by Reductive Cyclization

To a stirring mixture of bromide IntD1 (105 g), tetrabutylammoniumiodide (60 g, 162 mmol) and activated 3 Å molecular sieves in anhydrousacetonitrile (2 L), solid NaBH₄ (30 g, 793 mmol) was added. The reactionwas heated at 40° C. overnight. The mixture was then diluted withdichloromethane (2 L) and filtered through Celite®. After evaporation,the residue was dissolved in 500 ml ethyl acetate. The white solid(Bu₄NI or Bu₄NBr) was filtered. The ethyl acetate solution wasevaporated and purified by chromatography on silica gel using ethylacetate and hexane as eluent to give the acetal-triacetate IntD2(˜60-70% yield). TLC R_(f)=0.36, SiO₂ in 40% ethyl acetate/60% hexanes.

Preparation of IntD3 by De-Acetylation

To a 1000 ml flask was added triacetate IntD2 (55 g) and 500 ml ofmethanol. After stirring 30 min, the reagent NaOMe (2.7 g, 0.3 eq) wasadded and the reaction was stirred overnight. Additional NaOMe (0.9 g)was added to the reaction mixture and heated to 50° C. for 3 hr. Themixture was neutralized with Dowex 50W×8 cation resin, filtered andevaporated. The residue was purified by silica gel column to give 24 gof trihydroxy-acetal IntD3. TLC R_(f)=0.36 in SiO₂, 10% methanol/90%ethyl acetate.

Preparation of IntD4 by Benzylidene Formation

To a 1000 ml flask was added trihydroxy compound IntD3 (76 g) andbenzaldehyde dimethyl acetate (73 g, 1.3 eq). The mixture was stirredfor 10 min, after which D(+)-camphorsulfonic acid (8.5 g, CSA) wasadded. The mixture was heated at 50° C. for two hours. The reactionmixture was then transferred to separatory funnel containing ethylacetate (1.8 L) and sodium bicarbonate solution (600 ml). Afterseparation, the organic layer was washed with a second sodiumbicarbonate solution (300 ml) and brine (800 ml). The two sodiumcarbonate solutions were combined and extracted with ethyl acetate (600ml×2). The organic mixture was evaporated and purified by silica gelcolumn to give the benzylidene product IntD4 (77 g, 71% yield). TLCR_(f)=0.47, SiO₂ in 40% ethyl acetate/60% hexanes.

Preparation of IntD5 by Benzylation

To a 500 ml flask was added benzylidene acetal compound IntD4 (21 g,) in70 ml THF. To another flask (1000 ml) was added NaH (2 eq). The solutionof IntD4 was then transferred to the NaH solution at 0° C. The reactionmixture was stirred for 30 min, then benzyl bromide (16.1 ml, 1.9 eq) in30 ml THF was added. After stirring for 30 min, DMF (90 ml) was added tothe reaction mixture. Excess NaH was neutralized by careful addition ofacetic acid (8 ml). The mixture was evaporated and purified by silicagel column to give the benzyl derivative IntD5. (23 g) TLC R_(f)=0.69,SiO₂ in 40% ethyl acetate/60% hexanes.

Preparation of IntD6 by Deprotection of Benzylidene

To a 500 ml flask was added the benzylidene-acetal compound IntD5 (20 g)and 250 ml of dichloromethane, the reaction mixture was cooled to 0° C.using an ice-water-salt bath. Aqueous TFA (80%, 34 ml) was added to themixture and stirred over night. The mixture was evaporated and purifiedby silica gel column to give the dihydroxy derivative IntD6. (8 g, 52%).TLC R_(f)=0.79, SiO₂ in 10% methanol/90% ethyl acetate.

Preparation of IntD7 by Oxidation of 6-Hydroxyl

To a 5 L flask was added dihydroxy compound IntD6 (60 g), TEMPO (1.08g), sodium bromide (4.2 g), tetrabutylammonium chloride (5.35 g),saturated NaHCO₃ (794 ml) and EtOAc (1338 ml). The mixture was stirredover an ice-water bath for 30 min To another flask was added a solutionof NaOCl (677 ml), saturated NaHCO₃ (485 ml) and brine (794 ml). Thesecond mixture was added slowly to the first mixture (over about twohrs). The resulting mixture was then stirred overnight. The mixture wasseparated, and the inorganic layer was extracted with EtOAc (800 ml×2).The combined organic layers were washed with brine (800 ml). Evaporationof the organic layer gave 64 g crude carboxylic acid product IntD7 whichwas used in the next step use without purification. TLC R_(f)=0.04, SiO₂in 10% methanol/90% ethyl acetate.

Preparation of Monomer D by Benzylation of the Carboxylic Acid

To a solution of carboxylic acid derivative IntD7 (64 g) in 600 ml ofdichloromethane, was added benzyl alcohol (30 g) andN-hydroxybenzotriazole (80 g, HOBt). After stirring for 10 mintriethylamine (60.2 g) was added slowly. After stirring another 10 min,dicyclohexylcarbodiimide, (60.8 g, DCC) was added slowly and the mixturewas stirred overnight. The reaction mixture was filtered and the solventwas removed under reduced pressure followed by chromatography on silicagel to provide 60.8 g (75%, over two steps) of product, Monomer D. TLCR_(f)=0.51, SiO₂ in 40% ethyl acetate/60% hexanes.

Synthesis of the BA Dimer Step 1. Preparation of BMod1, Levulination ofMonomer B1

A 100 L reactor was charged with 7.207 Kg of Monomer B1 (21.3 moles, 1equiv), 20 L of dry tetrahydrofuran (THF) and agitated to dissolve. Whenclear, it was purged with nitrogen and 260 g of dimethylamino pyridine(DMAP, 2.13 moles, 0.1 equiv) and 11.05 L of diisopropylethylamine(DIPEA, 8.275 kg, 63.9 moles, 3 equiv) was charged into the reactor. Thereactor was chilled to 10-15° C. and 13.7 kg levulinic anhydride (63.9mol, 3 equiv) was transferred into the reactor. When the addition wascomplete, the reaction was warmed to ambient temperature and stirredovernight or 12-16 hours. Completeness of the reaction was monitored byTLC (40:60 ethyl acetate/hexane) and HPLC. When the reaction wascomplete, 20 L of 10% citric acid, 10 L of water and 25 L of ethylacetate were transferred into the reactor. The mixture was stirred for30 min and the layers were separated. The organic layer (EtOAc layer)was extracted with 20 L of water, 20 L 5% sodium bicarbonate and 20 L25% brine solutions. The ethyl acetate solution was dried in 4-6 Kg ofanhydrous sodium sulfate. The solution was evaporated to a syrup (bathtemp. 40° C.) and dried overnight. The yield of the isolated syrup ofBMod1 was 100%.

Synthesis of the BA Dimer Step 2. Preparation of BMod2, TFA Hydrolysisof BMod1

A 100 L reactor was charged with 9296 Kg of 4-Lev Monomer B1 (BMod1)(21.3 mol, 1 equiv). The reactor chiller was turned to <5° C. andstirring was begun, after which 17.6 L of 90% TFA solution (TFA, 213mole, 10 equiv) was transferred into the reactor. When the addition wascomplete, the reaction was monitored by TLC and HPLC. The reaction tookapproximately 2-3 hours to reach completion. When the reaction wascomplete, the reactor was chilled and 26.72 L of triethylamine (TEA,19.4 Kg, 191.7 mole, 0.9 equiv) was transferred into the reactor. Anadditional 20 L of water and 20 L ethyl acetate were transferred intothe reactor. This was stirred for 30 min and the layers were separated.The organic layer was extracted (EtOAc layer) with 20 L 5% sodiumbicarbonate and 20 L 25% brine solutions. The ethyl acetate solution wasdried in 4-6 Kg of anhydrous sodium sulfate. The solution was evaporatedto a syrup (bath temp. 40° C.). The crude product was purified in a 200L silica column using 140-200 L each of the following gradient profiles:50:50, 80:20 (EtOAc/heptane), 100% EtOAc, 5:95, 10:90 (MeOH/EtOAc). Thepure fractions were pooled and evaporated to a syrup. The yield of theisolated syrup, BMod2 was 90%.

Synthesis of the BA Dimer Step 3. Preparation of BMod3, Silylation ofBMod2

A 100 L reactor was charged with 6.755 Kg 4-Lev-1,2-DiOH Monomer B1(BMod2) (17.04 mol, 1 equiv), 2328 g of imidazole (34.2 mol, 2 equiv)and 30 L of dichloromethane. The reactor was purged with nitrogen andchilled to −20° C., then 5.22 L tert-butyldiphenylchloro-silane(TBDPS—Cl, 5.607 Kg, 20.4 mol, 1.2 equiv) was transferred into thereactor. When addition was complete, the chiller was turned off and thereaction was allowed to warm to ambient temperature. The reaction wasmonitored by TLC (40% ethyl acetate/hexane) and HPLC. The reaction tookapproximately 3 hours to reach completion. When the reaction wascomplete, 20 L of water and 10 L of DCM were transferred into thereactor and stirred for 30 min, after which the layers were separated.The organic layer (DCM layer) was extracted with 20 L water and 20 L 25%brine solutions. Dichloromethane solution was dried in 4-6 Kg ofanhydrous sodium sulfate. The solution was evaporated to a syrup (bathtemp. 40° C.). The yield of BMod3 was about 80%.

Synthesis of the BA Dimer Step 4. Preparation of BMod4, Benzoylation

A 100 L reactor was charged with 8.113 Kg of 4-Lev-1-Si-2-OH Monomer B1(BMod3) (12.78 mol, 1 equiv), 9 L of pyridine and 30 L ofdichloromethane. The reactor was purged with nitrogen and chilled to−20° C., after which 1.78 L of benzoyl chloride (2155 g, 15.34 mol, 1.2equiv) was transferred into the reactor. When addition was complete, thereaction was allowed to warm to ambient temperature. The reaction wasmonitored by TLC (40% ethyl acetate/heptane) and HPLC. The reaction tookapproximately 3 hours to reach completion. When the reaction wascomplete, 20 L of water and 10 L of DCM were transferred into thereactor and stirred for 30 min, after which the layers were separated.The organic layer (DCM layer) was extracted with 20 L water and 20 L 25%brine solutions. The DCM solution was dried in 4-6 Kg of anhydroussodium sulfate. The solution was evaporated to a syrup (bath temp. 40°C.). Isolated syrup BMod4 was obtained in 91% yield.

Synthesis of the BA Dimer Step 5. Preparation of BMod5, Desilylation

A 100 L reactor was charged with 8.601 Kg of 4-Lev-1-Si-2-Bz Monomer B1(BMod4) (11.64 mol, 1 equiv) in 30 L terahydrofuran. The reactor waspurged with nitrogen and chilled to 0° C., after which 5.49 Kg oftetrabutylammonium fluoride (TBAF, 17.4 mol, 1.5 equiv) and 996 mL (1045g, 17.4 mol, 1.5 equiv) of glacial acetic acid were transferred into thereactor. When the addition was complete, the reaction was stirred atambient temperature. The reaction was monitored by TLC (40:60 ethylacetate/hexane) and HPLC. The reaction took approximately 6 hours toreach completion. When the reaction was complete, 20 L of water and 10 Lof DCM were transferred into the reactor and stirred for 30 min, afterwhich the layers were separated. The organic layer (DCM layer) wasextracted with 20 L water and 20 L 25% brine solutions. Thedichloromethane solution was dried in 4-6 Kg of anhydrous sodiumsulfate. The solution was evaporated to a syrup (bath temp. 40° C.). Thecrude product was purified in a 200 L silica column using 140-200 L eachof the following gradient profiles: 10:90, 20:80, 30:70, 40:60, 50:50,60:40, 70:30, 80:20 (EtOAc/heptane) and 200 L 100% EtOAc. Pure fractionswere pooled and evaporated to a syrup. The intermediate BMod5 wasisolated as a syrup in 91% yield.

Synthesis of the BA Dimer Step 6: Preparation of BMod6, TCA Formation

A 100 L reactor was charged with 5.238 Kg of 4-Lev-1-OH-2-Bz Monomer B1(BMod5) (10.44 mol, 1 equiv) in 30 L of DCM. The reactor was purged withnitrogen and chilled to 10-15° C., after which 780 mL of diazabicycloundecene (DBU, 795 g, 5.22 mol, 0.5 equiv) and 10.47 L oftrichloroacetonitrile (TCA, 15.08 Kg, 104.4 mol, 10 equiv) weretransferred into the reactor. Stirring was continued and the reactionwas kept under a nitrogen atmosphere. After reagent addition, thereaction was allowed to warm to ambient temperature. The reaction wasmonitored by HPLC and TLC (40:60 ethyl acetate/heptane). The reactiontook approximately 2 hours to reach completion. When the reaction wascomplete, 20 L of water and 10 L of dichloromethane were transferredinto the reactor. This was stirred for 30 min and the layers wereseparated. The organic layer (DCM layer) was separated with 20 L waterand 20 L 25% brine solutions. The dichloromethane solution was dried in4-6 Kg of anhydrous sodium sulfate. The solution was evaporated to asyrup (bath temp. 40° C.). The crude product was purified in a 200 Lsilica column using 140-200 L each of the following gradient profiles:10:90, 20:80, 30:70, 40:60 and 50:50 (EtOAc/Heptane). Pure fractionswere pooled and evaporated to a syrup. The isolated yield of BMod6 was73%.

Synthesis of the BA Dimer Step 7. Preparation of AMod1, Acetylation ofMonomer A2

A 100 L reactor was charged with 6.772 Kg of Monomer A2 (17.04 mole, 1eq.), 32.2 L (34.8 Kg, 340.8 moles, 20 eq.) of acetic anhydride and 32 Lof dichloromethane. The reactor was purged with nitrogen and chilled to−20° C. When the temperature reached −20° C., 3.24 L (3.63 Kg, 25.68mol, 1.5 equiv) of boron trifluoride etherate (BF₃.Et₂O) was transferredinto the reactor. After complete addition of boron trifluoride etherate,the reaction was allowed to warm to room temperature. The completenessof the reaction was monitored by HPLC and TLC (30:70 ethylacetate/heptane). The reaction took approximately 3-5 hours forcompletion. When the reaction was complete, extraction was performedwith 3×15 L of 10% sodium bicarbonate and 20 L of water. The organicphase (DCM) was evaporated to a syrup (bath temp. 40° C.) and allowed todry overnight. The syrup was purified in a 200 L silica column using 140L each of the following gradient profiles: 5:95, 10:90, 20:80, 30:70,40:60 and 50:50 (EtOAc/heptane). Pure fractions were pooled andevaporated to a syrup. The isolated yield of AMod1 was 83%.

Synthesis of the BA Dimer Step 8. Preparation of AMod3,1-Methylation ofAMod1

A 100 L reactor was charged with 5891 g of acetyl Monomer A2 (AMod1)(13.98 mole, 1 eq.) in 32 L of dichloromethane. The reactor was purgedwith nitrogen and was chilled to 0° C., after which 2598 mL oftrimethylsilyl iodide (TMSI, 3636 g, 18 mol, 1.3 equiv) was transferredinto the reactor. When addition was complete, the reaction was allowedto warm to room temperature. The completeness of the reaction wasmonitored by HPLC and TLC (30:70 ethyl acetate/heptane). The reactiontook approximately 2-4 hours to reach completion. When the reaction wascomplete, the mixture was diluted with 20 L of toluene. The solution wasevaporated to a syrup and was co-evaporated with 3×6 L of toluene. Thereactor was charged with 36 L of dichloromethane (DCM), 3.2 Kg of dry 4Å Molecular Sieves, 15505 g (42 mol, 3 equiv) of tetrabutyl ammoniumiodide (TBAI) and 9 L of dry methanol. This was stirred until the TBAIwas completely dissolved, after which 3630 mL of diisopropyl-ethylamine(DIPEA, 2712 g, 21 moles, 1.5 equiv) was transferred into the reactor inone portion. The completion of the reaction was monitored by HPLC andTLC (30:70 ethyl acetate/heptane). The reaction took approximately 16hours for completion. When the reaction was complete, the molecularsieves were removed by filtration. Added were 20 L EtOAc and extractedwith 4×20 L of 25% sodium thiosulfate and 20 L 10% NaCl solutions. Theorganic layer was separated and dried with 8-12 Kg of anhydrous sodiumsulfate. The solution was evaporated to a syrup (bath temp. 40° C.). Thecrude product was purified in a 200 L silica column using 140-200 L eachof the following gradient profiles: 5:95, 10:90, 20:80, 30:70 and 40:60(EtOAc/heptane). The pure fractions were pooled and evaporated to giveintermediate AMod3 as a syrup. The isolated yield was 75%.

Synthesis of the BA Dimer Step 9. Preparation of AMod4, DeAcetylation ofAMod3

A 100 L reactor was charged with 4128 g of 1-Methyl 4,6-Diacetyl MonomerA2 (AMod3) (10.5 mol, 1 equiv) and 18 L of dry methanol and dissolved,after which 113.4 g (2.1 mol, 0.2 equiv) of sodium methoxide wastransferred into the reactor. The reaction was stirred at roomtemperature and monitored by TLC (40% ethyl acetate/hexane) and HPLC.The reaction took approximately 2-4 hours for completion. When thereaction was complete, Dowex 50W×8 cation resin was added in smallportions until the pH reached 6-8. The Dowex 50W×8 resin was filteredand the solution was evaporated to a syrup (bath temp. 40° C.). Thesyrup was diluted with 10 L of ethyl acetate and extracted with 20 Lbrine and 20 L water. The ethyl acetate solution was dried in 4-6 Kg ofanhydrous sodium sulfate. The solution was evaporated to a syrup (bathtemp. 40° C.) and dried overnight at the same temperature. The isolatedyield of the syrup AMod4 was about 88%.

Synthesis of the BA Dimer Step 10. Preparation of AMod5,6-Benzoylation

A 100 L reactor was charged with 2858 g of Methyl 4,6-diOH Monomer A2(AMod4) (9.24 mol, 1 equiv) and co-evaporated with 3×10 L of pyridine.When evaporation was complete, 15 L of dichloromethane, 6 L of pyridinewere transferred into the reactor and dissolved. The reactor was purgedwith nitrogen and chilled to −40° C. The reactor was charged with 1044mL (1299 g, 9.24 mol, 1 equiv) of benzoyl chloride. When the additionwas complete, the reaction was allowed to warm to −10° C. over a periodof 2 hours. The reaction was monitored by TLC (60% ethylacetate/hexane). When the reaction was completed, the solution wasevaporated to a syrup (bath temp. 40° C.). This was co-evaporated with3×15 L of toluene. The syrup was diluted with 40 L ethyl acetate.Extraction was carried out with 20 L of water and 20 L of brinesolution. The Ethyl acetate solution was dried in 4-6 Kg of anhydroussodium sulfate. The solution was evaporated to a syrup (bath temp. 40°C.). The crude product was purified in a 200 L silica column using140-200 L each of the following gradient profiles: 5:95, 10:90, 20:80,25:70 and 30:60 (EtOAc/heptane). The pure fractions were pooled andevaporated to a syrup. The isolated yield of the intermediate AMod5 was84%.

Synthesis of the BA Dimer Step 11. Preparation of BA1, Coupling of Amod5with BMod6

A 100 L reactor was charged with 3054 g of methyl 4-Hydroxy-Monomer A2(AMod5) from Step 10 (7.38 mol, 1 equiv) and 4764 g of4-Lev-1-TCA-Monomer B1 (BMod6) from Step 6 (7.38 mol, 1 equiv). Thecombined monomers were dissolved in 20 L of toluene and co-evaporated at40° C. Co evaporation was repeated with an additional 2×20 L of toluene,after which 30 L of dichloromethane (DCM) was transferred into thereactor and dissolved. The reactor was purged with nitrogen and waschilled to below −20° C. When the temperature was between −20° C. and−40° C., 1572 g (1404 mL, 11.12 moles, 1.5 equiv) of boron trifluorideetherate (BF₃.Et₂O) were transferred into the reactor. After completeaddition of boron trifluoride etherate, the reaction was allowed to warmto 0° C. and stirring was continued. The completeness of the reactionwas monitored by HPLC and TLC (40:70 ethyl acetate/heptane). Thereaction required 3-4 hours to reach completion. When the reaction wascomplete, 926 mL (672 g, 6.64 mol, 0.9 equiv) of triethylamine (TEA) wastransferred into the mixture and stirred for an additional 30 minutes,after which 20 L of water and 10 L of dichloromethane were transferredinto the reactor. The solution was stirred for 30 min and the layerswere separated. The organic layer (DCM layer) was separated with 2×20 Lwater and 20 L 25% 4:1 sodium chloride/sodium bicarbonate solution. Thedichloromethane solution was dried in 4-6 Kg of anhydrous sodiumsulfate. The solution was evaporated to a syrup (bath temp. 40° C.) andused in the next step. The isolated yield of the disaccharide BA1 wasabout 72%.

Synthesis of the BA Dimer Step 12, Removal of Levulinate Methyl [(methyl2-O-benzoyl-3-O-benzyl-α-L-Idopyranosyluronate)-(1→4)-2-azido-6-O-benzoyl-3-O-benzyl]-2-deoxy-α-D-glucopyranoside

A 100 L reactor was charged with 4.104 Kg of 4-Lev BA Dimer (BA1) (4.56mol, 1 equiv) in 20 L of THF. The reactor was purged with nitrogen andchilled to −20 to −25° C., after which 896 mL of hydrazine hydrate (923g, 18.24 mol, 4 equiv) was transferred into the reactor. Stirring wascontinued and the reaction was monitored by TLC (40% ethylacetate/heptane) and HPLC. The reaction took approximately 2-3 hour forthe completion, after which 20 L of 10% citric acid, 10 L of water and25 L of ethyl acetate were transferred into the reactor. This wasstirred for 30 min and the layers were separated. The organic layer(ETOAc layer) was extracted with 20 L 25% brine solutions. The ethylacetate solution was dried in 4-6 Kg of anhydrous sodium sulfate. Thesolution was evaporated to a syrup (bath temp. 40° C.). The crudeproduct was purified in a 200 L silica column using 140-200 L each ofthe following gradient profiles: 10:90, 20:80, 30:70, 40:60 and 50:50(EtOAc/heptane). The pure fractions were pooled and evaporated todryness. The isolated yield of the BA Dimer was 82%. Formula:C₄₂H₄₃N₃O₁₃; Mol. Wt. 797.80.

Synthesis of the EDC Trimer Step 1. Preparation of EMod1, Acetylation

A 100 L reactor was charged with 16533 g of Monomer E (45 mole, 1 eq.),21.25 L acetic anhydride (225 mole, 5 eq.) and 60 L of dichloromethane.The reactor was purged with nitrogen and was chilled to −10° C. When thetemperature was at −10° C., 1.14 L (1277 g) of boron trifluorideetherate (BF₃.Et₂O, 9.0 moles, 0.2 eq) were transferred into thereactor. After the complete addition of boron trifluoride etherate, thereaction was allowed to warm to room temperature. The completeness ofthe reaction was monitored by TLC (30:70 ethyl acetate/heptane) andHPLC. The reaction took approximately 3-6 hours to reach completion.When the reaction was completed, the mixture was extracted with 3×50 Lof 10% sodium bicarbonate and SOL of water. The organic phase (DCM) wasevaporated to a syrup (bath temp. 40° C.) and allowed to dry overnight.The isolated yield of EMod1 was 97%.

Synthesis of the EDC Trimer Step 2. Preparation of EMod2, De-Acetylationof Azidoglucose

A 100 L reactor was charged with 21016 g of 1,6-Diacetyl Monomer E(EMod1) (45 mole, 1 eq.), 5434 g of hydrazine acetate (NH₂NH₂.HOAc,24.75 mole, 0.55 eq.) and 50 L of DMF (dimethyl formamide). The solutionwas stirred at room temperature and the reaction was monitored by TLC(30% ethyl acetate/hexane) and HPLC. The reaction took approximately 2-4hours for completion. When the reaction was completed, 50 L ofdichloromethane and 40 L of water were transferred into the reactor.This was stirred for 30 minutes and the layers were separated. This wasextracted with an additional 40 L of water and the organic phase wasdried in 6-8 Kg of anhydrous sodium sulfate. The solution was evaporatedto a syrup (bath temp. 40° C.) and dried overnight at the sametemperature. The syrup was purified in a 200 L silica column using140-200 L each of the following gradient profiles: 20:80, 30:70, 40:60and 50:50 (EtOAc/heptane). Pure fractions were pooled and evaporated toa syrup. The isolated yield of intermediate EMod2 was 100%.

Synthesis of the EDC Trimer Step 3. Preparation of EMod3, Formation of1-TCA

A 100 L reactor was charged with 12752 g of 1-Hydroxy Monomer E (EMod2)(30 mole, 1 eq.) in 40 L of dichloromethane. The reactor was purged withnitrogen and stirring was started, after which 2.25 L of DBU (15 moles,0.5 eq.) and 15.13 L of trichloroacetonitrile (150.9 moles, 5.03 eq)were transferred into the reactor. Stirring was continued and thereaction was kept under nitrogen. After the reagent addition, thereaction was allowed to warm to ambient temperature. The reaction wasmonitored by TLC (30:70 ethyl acetate/Heptane) and HPLC. The reactiontook approximately 2-3 hours to reach completion. When the reaction wascomplete, 40 L of water and 20 L of DCM were charged into the reactor.This was stirred for 30 min and the layers were separated. The organiclayer (DCM layer) was extracted with 40 L water and the DCM solution wasdried in 6-8 Kg of anhydrous sodium sulfate. The solution was evaporatedto a syrup (bath temp. 40° C.). The crude product was purified in a 200L silica column using 140-200 L each of the following gradient profiles:10:90 (DCM/EtOAc/heptane), 20:5:75 (DCM/EtOAc/heptane) and 20:10:70DCM/EtOAc/heptane). Pure fractions were pooled and evaporated to giveIntermediate EMod3 as a syrup. Isolated yield was 53%.

Synthesis of the EDC Trimer Step 4. Preparation of ED Dimer, Coupling ofE-TCA with Monomer D

A 100 L reactor was charged with 10471 g of 6-Acetyl-1-TCA Monomer E(EMod3) (18.3 mole, 1 eq., FW: 571.8) and 6594 g of Monomer D (16.47mole, 0.9 eq, FW: 400.4). The combined monomers were dissolved in 20 Ltoluene and co-evaporated at 40° C. This was repeated withco-evaporation with an additional 2×20 L of toluene, after which 60 L ofdichloromethane (DCM) were transferred into the reactor and dissolved.The reactor was purged with nitrogen and was chilled to −40° C. When thetemperature was between −30° C. and −40° C., 2423 g (2071 mL, 9.17moles, 0.5 eq) of TES Triflate were transferred into the reactor. Aftercomplete addition of TES Triflate the reaction was allowed to warm andstirring was continued. The completeness of the reaction was monitoredby HPLC and TLC (35:65 ethyl acetate/Heptane). The reaction required 2-3hours to reach completion. When the reaction was completed, 2040 mL oftriethylamine (TEA, 1481 g, 0.8 eq.) were transferred into the reactorand stirred for an additional 30 minutes. The organic layer (DCM layer)was extracted with 2×20 L 25% 4:1 sodium chloride/sodium bicarbonatesolution. The dichloromethane solution was dried in 6-8 Kg of anhydroussodium sulfate. The syrup was purified in a 200 L silica column using140-200 L each of the following gradient profiles: 15:85, 20:80, 25:75,30:70 and 35:65 (EtOAc/heptane). Pure fractions were pooled andevaporated to a syrup. The ED Dimer was obtained in 81% isolated yield.

Synthesis of the EDC Trimer Step 5. Preparation of ED1 TFA, Hydrolysisof ED Dimer

A 100 L reactor was charged with 7.5 Kg of ED Dimer (9.26 mol, 1 equiv).The reactor was chilled to <5° C. and 30.66 L of 90% TFA solution (TFA,370.4 mol, 40 equiv) were transferred into the reactor. When theaddition was completed the reaction was allowed to warm to roomtemperature. The reaction was monitored by TLC (40:60 ethylacetate/hexanes) and HPLC. The reaction took approximately 3-4 hours toreach completion. When the reaction was completed, was chilled and 51.6L of triethylamine (TEA, 37.5 Kg, 370.4 mole) were transferred into thereactor, after which 20 L of water & 20 L ethyl acetate were transferredinto the reactor. This was stirred for 30 min and the layers wereseparated. The organic layer (EtOAc layer) was extracted with 20 L 5%sodium bicarbonate and 20 L 25% brine solutions. Ethyl acetate solutionwas dried in 4-6 Kg of anhydrous sodium sulfate. The solution wasevaporated to a syrup (bath temp. 40° C.). The crude product waspurified in a 200 L silica column using 140-200 L each of the followinggradient profiles: 20:80, 30:70, 40:60, 50:50, 60:40 (EtOAc/heptane).The pure fractions were pooled and evaporated to a syrup. Isolated yieldof ED1 was about 70%.

Synthesis of the EDC Trimer Step 6. Preparation of ED2, Silylation ofED1

A 100 L reactor was charged with 11000 g of 1,2-diOH ED Dimer (ED1)(14.03 mol, 1 equiv), 1910.5 g of imidazole (28.06 mol, 2 equiv) and 30L of dichloromethane. The reactor was purged with nitrogen and chilledto −20° C., after which 3.53 L butyldiphenylchloro-silane (TBDPS—Cl,4.628 Kg, 16.835 mol, 1.2 equiv) was charged into the reactor. When theaddition was complete, the chiller was turned off and the reaction wasallowed to warm to ambient temperature. The reaction was monitored byTLC (50% ethyl acetate/hexane) and HPLC. The reaction required 4-6 hoursto reach completion. When the reaction was completed, 20 L of water and10 L of dichloromethane were transferred into the reactor and stirredfor 30 min and the layers were separated. The organic layer (DCM layer)was extracted with 20 L water and 20 L 25% brine solutions.Dichloromethane solution was dried in 4-6 Kg of anhydrous sodiumsulfate. The solution was evaporated to a syrup (bath temp. 40° C.).Intermediate ED2 was obtained in 75% isolated yield.

Synthesis of the EDC Trimer Step 7. Preparation of ED3, D-Levulination

A 100 L reactor was charged with 19800 g of 1-Silyl ED Dimer (ED2)(19.37 moles, 1 equiv) and 40 L of dry tetrahydrofuran (THF) andagitated to dissolve. The reactor was purged with nitrogen and 237 g ofdimethylaminopyridine (DMAP, 1.937 moles, 0.1 equiv) and 10.05 L ofdiisopropylethylamine (DIPEA, 63.9 moles, 3 equiv) were transferred intothe reactor. The reactor was chilled to 10-15° C. and kept under anitrogen atmosphere, after which 12.46 Kg of levulinic anhydride (58.11moles, 3 eq) was charged into the reactor. When the addition wascomplete, the reaction was warmed to ambient temperature and stirredovernight or 12-16 hours. The completeness of the reaction was monitoredby TLC (40:60 ethyl acetate/hexane) and by HPLC. 20 L of 10% citricacid, 10 L of water and 25 L of ethyl acetate were transferred into thereactor. This was stirred for 30 min and the layers were separated. Theorganic layer (EtOAc layer) was extracted with 20 L of water, 20 L 5%sodium bicarbonate and 20 L 25% brine solutions. The ethyl acetatesolution was dried in 6-8 Kg of anhydrous sodium sulfate. The solutionwas evaporated to a syrup (bath temp. 40° C.). The ED3 yield was 95%.

Synthesis of the EDC Trimer Step 8. Preparation of ED4, Desilylation ofED3

A 100 L reactor was charged with 19720 g of 1-Silyl-2-Lev ED Dimer (ED3)(17.6 mol, 1 equiv) in 40 L of THF. The reactor was chilled to 0° C.,after which 6903 g of tetrabutylammonium fluoride trihydrate (TBAF, 26.4mol, 1.5 equiv) and 1511 mL (26.4 mol, 1.5 equiv) of glacial acetic acidwere transferred into the reactor. When the addition was complete, thereaction was stirred and allowed to warm to ambient temperature. Thereaction was monitored by TLC (40:60 ethyl acetate/hexane) and HPLC. Thereaction required 3 hours to reach completion. When the reaction wascompleted, 20 L of water and 10 L of dichloromethane were transferredinto the reactor and stirred for 30 min and the layers were separated.The organic layer (DCM layer) was extracted with 20 L water and 20 L 25%brine solutions. The dichloromethane solution was dried in 6-8 Kg ofanhydrous sodium sulfate. The solution was evaporated to a syrup (bathtemp. 40° C.). The crude product was purified using a 200 L silicacolumn using 140-200 L each of the following gradient profiles: 10:90,20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20 (EtOAc/heptane) and 200L 100% EtOAc. The pure fractions were pooled and evaporated to a syrupand used in the next step. The isolated yield of ED4 was about 92%.

Synthesis of the EDC Trimer Step 9. Preparation of ED5, TCA Formation

A 100 L reactor was charged with 14420 g of 1-OH-2-Lev ED Dimer (ED4)(16.35 mol, 1 equiv) in 30 L of dichloromethane. The reactor was purgedwith nitrogen and stirring was begun, after which 1222 mL ofdiazabicycloundecene (DBU, 8.175 mol, 0.5 equiv) and 23.61 Kg oftrichloroacetonitrile (TCA, 163.5 mol, 10 equiv) were transferred intothe reactor. Stirring was continued and the reaction was kept undernitrogen. After reagent addition, the reaction was allowed to warm toambient temperature. The reaction was monitored by HPLC and TLC (40:60ethyl acetate/heptane). The reaction took approximately 2 hours forreaction completion. When the reaction was completed, 20 L of water and10 L of DCM were transferred into the reactor and stirred for 30 min andthe layers were separated. The organic layer (DCM layer) was extractedwith 20 L water and 20 L 25% brine solutions. The dichloromethanesolution was dried in 6-8 Kg of anhydrous sodium sulfate. The solutionwas evaporated to a syrup (bath temp. 40° C.). The crude product waspurified using a 200 L silica column using 140-200 L each of thefollowing gradient profiles: 10:90, 20:80, 30:70, 40:60 and 50:50(EtOAc/heptane). The pure fractions were pooled and evaporated to asyrup and used in the next step. The isolated yield of intermediate ED5was about 70%.

Synthesis of the EDC Trimer Step 10. Preparation of EDC Trimer, Couplingof ED5 with Monomer C6-O-acetyl-2-azido-3,4-di-O-benzyl-2-deoxy-α-D-glucopyranosyl-(1→4)-benzyl(3-O-benzyl-2-O-levulinoyl)-β-D-glucopyranosyluronate-(1→4)-(3-O-acetyl-1,6-anhydro-2-azido)-2-deoxy-β-D-glucopyranose

A 100 L reactor was charged with 12780 g of 2-Lev 1-TCA ED Dimer (ED5)(7.38 mole, 1 eq., FW) and 4764 g of Monomer C (7.38 mole, 1 eq). Thecombined monomers were dissolved in 20 L toluene and co-evaporated at40° C. Repeated was co-evaporation with an additional 2×20 L of toluene,after which 60 L of dichloromethane (DCM) was transferred into thereactor and dissolved. The reactor was purged with nitrogen and chilledto −20° C. When the temperature was between −20 and −10° C., 2962 g(11.2 moles, 0.9 eq) of TES Triflate were transferred into the reactor.After complete addition of TES Triflate the reaction was allowed to warmto 5° C. and stirring was continued. Completeness of the reaction wasmonitored by HPLC and TLC (35:65 ethyl acetate/Heptane). The reactionrequired 2-3 hours to reach completion. When the reaction was completed,1133 g of triethylamine (TEA, 0.9 eq.) were transferred into the reactorand stirred for an additional 30 minutes. The organic layer (DCM layer)was extracted with 2×20 L 25% 4:1 sodium chloride/sodium bicarbonatesolution. Dichloromethane solution was dried in 6-8 Kg of anhydroussodium sulfate. The syrup was purified in a 200 L silica column using140-200 L each of the following gradient profiles: 15:85, 20:80, 25:75,30:70 and 35:65 (EtOAc/heptane). Pure fractions were pooled andevaporated to a syrup. The isolated yield of EDC Trimer was 48%.Formula: C₅₅H₆₀N₆O₁₈; Mol. Wt. 1093.09. The ¹H NMR spectrum (d6-acetone)of the EDC trimer is shown in FIG. 3.

Preparation of EDC1 Step 1: Anhydro Ring Opening & Acetylation6-O-acetyl-2-azido-2-deoxy-3,4-di-O-benzyl-α-D-glucopyranosyl-(1→4)-O-[benzyl3-O-benzyl-2-O-levulinoyl-β-D-glucopyranosyluronate]-(1→4)-O-2-azido-2-deoxy-1,3,6-tri-O-acetyl-β-D-glucopyranose

7.0 Kg (6.44 mol) of EDC Trimer was dissolved in 18 L anhydrousDichloromethane. 6.57 Kg (64.4 mol, 10 eq) of Acetic anhydride wasadded. The solution was cooled to −45 to −35° C. and 1.82 Kg (12.9 mol,2 eq) of Boron Trifluoride etherate was added slowly. Upon completion ofaddition, the mixture was warmed to 0-10° C. and kept at thistemperature for 3 hours until reaction was complete by TLC and HPLC. Thereaction was cooled to −20° C. and cautiously quenched and extractedwith saturated solution of sodium bicarbonate (3×20 L) while maintainingthe mixture temperature below 5° C. The organic layer was extracted withbrine (1×20 L), dried over anhydrous sodium sulfate, and concentratedunder vacuum to a syrup. The resulting syrup of EDC1 (6.74 Kg) was usedfor step 2 without further purification. The ¹H NMR spectrum(d6-acetone) of the EDC-1 trimer is shown in FIG. 4.

Preparation of EDC2 Step 2: Deacetylation6-O-acetyl-2-azido-2-deoxy-3,4-di-O-benzyl-α-D-glucopyranosyl-(1→4)-O-[benzyl3-O-benzyl-2-O-levulinoyl-β-D-glucopyranosyluronate]-(1→4)-O-2-azido-2-deoxy-3,6-di-O-acetyl-β-D-glucopyranose

The crude EDC1 product obtained from step 1 was dissolved in 27 L ofTetrahydrofuran and chilled to 15-20° C., after which 6 Kg (55.8 mol) ofbenzylamine was added slowly while maintaining the reaction temperaturebelow 25° C. The reaction mixture was stirred for 5-6 hours at 10-15° C.Upon completion, the mixture was diluted with ethyl acetate andextracted and quenched with 10% citric acid solution (2×20 L) whilemaintaining the temperature below 25° C. The organic layer was extractedwith 10% NaCl/1% sodium bicarbonate (1×20 L). The extraction wasrepeated with water (1×10 L), dried over anhydrous sodium sulfate andevaporated under vacuum to a syrup. Column chromatographic separationusing silica gel yielded 4.21 Kg (57% yield over 2 steps) of EDC2[ alsoreferred to as 1-Hydroxy-6-Acetyl EDC Trimer]. The ¹H NMR spectrum(d6-acetone) of the EDC-2 trimer is shown in FIG. 5.

Preparation of EDC3 Step 3: Formation of TCA Derivative6-O-acetyl-2-azido-2-deoxy-3,4-di-O-benzyl-α-D-glucopyranosyl-(1→4)-O-[benzyl3-O-benzyl-2-O-levulinoyl-β-D-glucopyranosyluronate]-(1→4)-O-2-azido-2-deoxy-3,6-di-O-acetyl-1-O-trichloroacetimidoyl-β-D-glucopyranose

4.54 Kg (3.94 mol) of EDC2 was dissolved in 20 L of Dichloromethane.11.4 Kg (78.8 mol, 20 eq) of Trichloroacetonitrile was added. Thesolution was cooled to −15 to −20° C. and 300 g (1.97 mol, 0.5 eq) ofDiazabicycloundecene was added. The reaction was allowed to warm to0-10° C. and stirred for 2 hours or until reaction was complete. Uponcompletion, water (20 L) was added and the reaction was extracted withan additional 10 L of DCM. The organic layer was extracted with brine(1×20 L), dried over anhydrous sodium sulfate, and concentrated undervacuum to a syrup. Column chromatographic separation using silica geland 20-60% ethyl acetate/heptane gradient yielded 3.67 Kg (72% yield) of1-TCA derivative, EDC3. The ¹H NMR spectrum (d6-acetone) of the EDC-3trimer is shown in FIG. 6.

Preparation of EDCBA1 Step 4: Coupling of EDC3 with BA Dimer MethylO-6-O-acetyl-2-azido-2-deoxy-3,4-di-O-benzyl-α-D-glucopyranosyl)-(1→4)-O-[benzyl3-O-benzyl-2-O-levulinoyl-β-D-glucopyranosyluronate]-(1→4)-O-2-azido-2-deoxy-3,6-di-O-acetyl-α-D-glucopyranosyl-(1→4)-O-[methyl2-O-benzoyl-3-O-benzyl-α-L-Idopyranosyluronate]-(1→4)-2-azido-6-O-benzoyl-3-O-benzyl-2-deoxy-α-D-glucopyranoside

3.67 Kg (2.83 mol) of EDC3 and 3.16 Kg (3.96 mol, 1.4 eq) of BA Dimerwas dissolved in 7-10 L of Toluene and evaporated to dryness. Theresulting syrup was coevaporated with Toluene (2×15 L) to remove water.The dried syrup was dissolved in 20 L of anhydrous Dichloromethane,transferred to the reaction flask, and cooled to −15 to −20° C. 898 g(3.4 mol, 1.2 eq) of triethylsilyl triflate was added while maintainingthe temperature below −5° C. When the addition was complete, thereaction was immediately warmed to −5 to 0° C. and stirred for 3 hours.The reaction was quenched by slowly adding 344 g (3.4 mol, 1.2 eq) ofTriethylamine. Water (15 L) was added and the reaction was extractedwith an additional 10 L of DCM. The organic layer was extracted with a25% 4:1 Sodium Chloride/Sodium Bicarbonate solution (2×20 L), dried overanhydrous sodium sulfate, and evaporated under vacuum to a syrup. Theresulting syrup of the pentasaccharide, EDCBA1 was used for step 5without further purification. The ¹H NMR spectrum (d6-acetone) of theEDCBA-1 pentamer is shown in FIG. 7.

Preparation of EDCBA2 Step 5: Hydrolysis of Levulinyl moiety MethylO-6-O-acetyl-2-azido-2-deoxy-3,4-di-O-benzyl-α-D-glucopyranosyl)-(1→4)—O-[benzyl3-O-benzyl-β-D-glucopyranosyluronate]-(1→4)-O-2-azido-2-deoxy-3,6-di-O-acetyl-α-D-glucopyranosyl)-(1→4)-O-[methyl2-O-benzoyl-3-O-benzyl-α-L-Idopyranosyluronate]-(1→4)-2-azido-6-O-benzoyl-3-O-benzyl-2-deoxy-α-D-glucopyranoside

The crude EDCBA1 from step 4 was dissolved in 15 L of Tetrahydrofuranand chilled to −20 to −25° C. A solution containing 679 g (13.6 mol) ofHydrazine monohydrate and 171 g (1.94 mol) of Hydrazine Acetate in 7 Lof Methanol was added slowly while maintaining the temperature below−20° C. When the addition was complete, the reaction mixture was allowedto warm to 0-10° C. and stirred for several hours until the reaction iscomplete, after which 20 L of Ethyl acetate was added and the reactionwas extracted with 10% citric acid (2×12 L). The organic layer waswashed with water (1×12 L), dried over anhydrous sodium sulfate, andevaporated under vacuum to a syrup. Column chromatographic separationusing silica gel and 10-45% ethyl acetate/heptane gradient yielded 2.47Kg (47.5% yield over 2 steps) of EDCBA2. The ¹H NMR spectrum(d6-acetone) of the EDCBA-2 pentamer is shown in FIG. 8.

Preparation of EDCBA Pentamer Step 6: THP Formation MethylO-6-O-acetyl-2-azido-2-deoxy-3,4-di-O-benzyl-α-D-glucopyranosyl-(1→4)-O-[benzyl3-O-benzyl-2-O-tetrahydropyranyl-β-D-glucopyranosyluronate]-(1→4)-O-2-azido-2-deoxy-3,6-di-O-acetyl-α-D-glucopyranosyl-(1→4)-O-[methyl2-O-benzoyl-3-O-benzyl-α-L-Idopyranosyluronate]-(1→4)-2-azido-6-O-benzoyl-3-O-benzyl-2-deoxy-α-D-glucopyranoside

2.47 Kg (1.35 mol) of EDCBA2 was dissolved in 23 L Dichloroethane andchilled to 10-15° C., after which 1.13 Kg (13.5 mol, 10 eq) ofDihydropyran and 31.3 g (0.135 mol, 0.1 eq) of Camphorsulfonic acid wereadded. The reaction was allowed warm to 20-25° C. and stirred for 4-6hours until reaction was complete. Water (15 L) was added and thereaction was extracted with an additional 10 L of DCE. The organic layerwas extracted with a 25% 4:1 Sodium Chloride/Sodium Bicarbonate solution(2×20 L), dried over anhydrous sodium sulfate, and evaporated undervacuum to a syrup. Column chromatographic separation using silica geland 10-35% ethyl acetate/heptane gradient yielded 2.28 Kg (88.5% yield)of fully protected EDCBA Pentamer. The ¹H NMR spectrum (d6-acetone) ofthe EDCBA pentamer is shown in FIG. 9.

Preparation of API1 Step 1: Saponification MethylO-2-azido-2-deoxy-3,4-di-O-benzyl-α-D-glucopyranosyl-(1→4)-O-3-O-benzyl-2-O-tetrahydropyranyl-β-D-glucopyranosyluronosyl-(1→4)-O-2-azido-2-deoxy-α-D-glucopyranosyl-(1→4)-O-3-O-benzyl-α-L-Idopyranosyluronosyl-(1→4)-2-azido-3-O-benzyl-2-deoxy-α-D-glucopyranosidedisodium salt

To a solution of 2.28 Kg (1.19 mol) of EDCBA Pentamer in 27 L of Dioxaneand 41 L of Tetrahydrofuran was added 45.5 L of 0.7 M (31.88 mol, 27 eq)Lithium hydroxide solution followed by 5.33 L of 30% Hydrogen peroxide.The reaction mixture was stirred for 10-20 hours to remove the acetylgroups. Then, 10 L of 4 N (40 mol, 34 eq) sodium hydroxide solution wasadded. The reaction was allowed to stir for an additional 24-48 hours tohydrolyze the benzyl and methyl esters completely. The reaction was thenextracted with ethyl acetate. The organic layer was extracted with brinesolution and dried with anhydrous sodium sulfate. Evaporation of thesolvent under vacuum gave a syrup of API1 [ also referred to asEDCBA(OH)₅] which was used for the next step without furtherpurification.

Preparation of API2 Step 2: O-Sulfonation MethylO-2-azido-2-deoxy-3,4-di-O-benzyl-6-O-sulfo-α-D-glucopyranosyl-(1→4)-O-3-O-benzyl-2-O-tetrahydropyranyl-β-D-glucopyranosyluronosyl-(1→4)-O-2-azido-2-deoxy-3,6-di-O-sulfo-α-D-glucopyranosyl-(1→4)-O-3-O-benzyl-2-O-sulfo-α-L-idopyranuronosyl-(1→4)-2-azido-2-deoxy-6-O-sulfo-α-D-glucopyranoside,heptasodium salt

The crude product of API1 [ aka EDCBA(OH)₅] obtained in step 1 wasdissolved in 10 L Dimethylformamide. To this was added a previouslyprepared solution containing 10.5 Kg (66 moles) of sulfurtrioxide-pyridine complex in 10 L of Pyridine and 25 L ofDimethylformamide. The reaction mixture was heated to 50° C. over aperiod of 45 min. After stiffing at 1.5 hours at 50° C., the reactionwas cooled to 20° C. and was quenched into 60 L of 8% sodium bicarbonatesolution that was kept at 10° C. The pH of the quench mixture wasmaintained at pH 7-9 by addition of sodium bicarbonate solution. Whenall the reaction mixture has been transferred, the quench mixture wasstirred for an additional 2 hours and pH was maintained at pH 7 orgreater. When the pH of quench has stabilized, it was diluted with waterand the resulting mixture was purified using a preparative HPLC columnpacked with Amberchrom CG161-M and eluted with 90%-10% SodiumBicarbonate (5%) solution/Methanol over 180 min. The pure fractions wereconcentrated under vacuum and was then desalted using a size exclusionresin or gel filtration (Biorad) G25 to give 1581 g (65.5% yield over 2steps) of API2 [ also referred to as EDCBA(OSO₃)₅]. The ¹H NMR spectrum(d6-acetone) of API-2 pentamer is shown in FIG. 10.

Preparation of API3 Step 3: Hydrogenation MethylO-2-amino-2-deoxy-6-O-sulfo-α-D-glucopyranosyl-(1→4)-O-2-O-tetrahydropyranyl-β-D-glucopyranosyluronosyl-(1→4)-O-2-amino-2-deoxy-3,6-di-O-sulfo-α-D-glucopyranosyl-(1→4)-O-2-O-sulfo-α-L-idopyranuronosyl-(1→4)-2-amino-2-deoxy-6-O-sulfo-α-D-glucopyranoside,heptasodium salt

A solution of 1581 g (0.78 mol) of O-Sulfated pentasaccharide API2 in 38L of Methanol and 32 L of water was treated with 30 wt % of Palladium inActivated carbon under 100 psi of Hydrogen pressure at 60-65° C. for 60hours or until completion of reaction. The mixture was then filteredthrough 1.0μ and 0.2μ filter cartridges and the solvent evaporated undervacuum to give 942 g (80% yield) of API3 [ also referred to asEDCBA(OSO₃)₅(NH₂)₃]. The ¹H NMR spectrum (d6-acetone) of API-3 pentameris shown in FIG. 11.

Preparation of Fondaparinux Sodium Step 4: N-Sulfation & Removal of THPMethylO-2-deoxy-6-O-sulfo-2-(sulfoamino)-α-D-glucopyranosyl-(1→4)—O-β-D-glucopyranuronosyl-(1→4)-O-2-deoxy-3,6-di-O-sulfo-2-(sulfoamino)-α-D-glucopyranosyl-(1→4)-O-2-O-sulfo-α-L-idopyranuronosyl-(1→4)-2-deoxy-6-O-sulfo-2-(sulfoamino)-α-D-glucopyranoside,decasodium salt

To a solution of 942 g (0.63 mol) of API3 in 46 L of water was slowlyadded 3.25 Kg (20.4 mol, 32 eq) of Sulfur trioxide-pyridine complex,maintaining the pH of the reaction mixture at pH 9-9.5 during theaddition using 2 N sodium hydroxide solution. The reaction was allowedto stir for 4-6 hours at pH 9.0-9.5. When reaction was complete, the pHwas adjusted to pH 7.0 using 50 mM solution of Ammonium acetate at pH3.5. The resulting N-sulfated EDCBA(OSO₃)₅(NHSO₃)₃ mixture was purifiedusing Ion-Exchange Chromatographic Column (Varian Preparative 15 cm HiQColumn) followed by desalting using a size exclusion resin or gelfiltration (Biorad G25). The resulting mixture was then treated withactivated charcoal and the purification by ion-exchange and desaltingwere repeated to give 516 g (47.6% yield) of the purified FondaparinuxSodium form.

Analysis of the Fondaparinux sodium identified the presence of P1, P2,P3, and P4 in the fondaparinux. P1, P2, P3, and P4 were identified bystandard analytical methods.

1. A compound of Formula I

wherein R₁ is levulinyl (Lev) or tetrahydropyran (THP); R₂ is —O⁻ or asalt thereof, —OH, —OAcyl, or —OSO₃ ⁻ or a salt thereof; R₃ is H, benzylor a protecting group removable by hydrogenation; R₄ is N₃ (azide), NH₂,NH-protecting group, or NHSO₃ ⁻ or a salt thereof; R₅ is C₁-C₆ alkyl;and R₆ and R₇ are independently selected from —CO₂ ⁻ or a salt thereof,—CO₂H, —CO₂R_(x) (where R_(x) is a C₁-C₆ alkyl, aryl, C₁-C₄alkoxy(aryl), aryl(C₁-C₆ alkyl), or C₁-C₄ alkoxy(aryl)(C₁-C₆ alkyl));and wherein said compound has alpha (α) stereochemistry at the carbonbearing the —OR₅ group.
 2. The compound of claim 1 wherein R₂ is—O-acetyl or —O-benzoyl.
 3. The compound of claim 1 wherein R₂ is —O⁻,—ONa, —OLi, —OK or —OCs.
 4. The compound of claim 1, wherein R₂ is —OSO₃⁻, —OSO₃Na, —OSO₃Li, —OSO₃K or —OSO₃Cs.
 5. The compound of claim 1,wherein R₅ is methyl.
 6. The compound of claim 1, wherein R₃ is benzylor p-methoxybenzyl.
 7. The compound of claim 1, wherein R₃ is —CO₂ ⁻,—CO₂Na, —CO₂Li, —CO₂K or —CO₂Cs.
 8. The compound of claim 1, wherein R₁is levulinyl (Lev), R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃(azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me.
 9. Thecompound of claim 1, wherein R₁ is tetrahydropyran (THP), R₂ is —OAcetylor —OBenzoyl, R₃ is benzyl, R₄ is N₃ (azide), R₅ is methyl, R₆ is—CO₂CH₂C₆H₅ and R₇ is —CO₂Me.
 10. The compound of claim 1, wherein R₁ istetrahydropyran (THP), R₂ is —O⁻ or a salt thereof, R₃ is benzyl, R₄ isN₃ (azide), R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or a salt thereof.11. The compound of claim 1, wherein R₁ is tetrahydropyran (THP), R₂ is—OSO₃ ⁻ or a salt thereof, R₃ is benzyl, R₄ is N₃ (azide), R₅ is methyl,and R₆ and R₇ are —CO₂ ⁻ or a salt thereof.
 12. The compound of claim 1,wherein R₁ is tetrahydropyran (THP), R₂ is —OSO₃ ⁻ or a salt thereof, R₃is H, R₄ is NH₂, R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or a saltthereof.
 13. The compound of claim 1, wherein R₁ is tetrahydropyran(THP), R₂ is —OSO₃Na, R₃ is H, R₄ is NHSO₃Na, R₅ is methyl, and R₆ andR₇ are —CO₂Na.
 14. A compound of Formula I

wherein R₁ is H, R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃(azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me. 15-42.(canceled)
 43. A compound selected from:


44. (canceled)
 45. A composition comprising (i) Fondaparinux sodium and(ii) a compound selected from:

and combinations thereof.
 46. The composition of claim 45, wherein thecomposition contains at least 95% by weight of Fondaparinux sodium andup to 0.2% of each of compounds P2, P3, and P4.
 47. The composition ofclaim 45, further comprising a compound of formula:


48. A composition comprising Fondaparinux sodium and a compoundaccording to claim
 1. 49. A composition comprising Fondaparinux sodiumand a compound selected from compounds of Formula I:

in which (a) R₁ is levulinyl (Lev), R₂ is —OAcetyl or —OBenzoyl, R₃ isbenzyl, R₄ is N₃ (azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is—CO₂Me; (b) R₁ is tetrahydropyran (THP), R₂ is —OAcetyl or —OBenzoyl, R₃is benzyl, R₄ is N₃ (azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is—CO₂Me; (c) R₁ is tetrahydropyran (THP), R₂ is —O⁻ or a salt thereof, R₃is benzyl, R₄ is N₃ (azide), R₅ is methyl, and R₆ and R₇ are —CO₂ ⁻ or asalt thereof; (d) R₁ is tetrahydropyran (THP), R₂ is —OSO₃ ⁻ or a saltthereof, R₃ is benzyl, R₄ is N₃ (azide), R₅ is methyl, and R₆ and R₇ are—CO₂ ⁻ or a salt thereof; (e) R₁ is tetrahydropyran (THP), R₂ is —OSO₃ ⁻or a salt thereof, R₃ is H, R₄ is NH₂, R₅ is methyl, and R₆ and R₇ are—CO₂ ⁻ or a salt thereof; (f) R₁ is tetrahydropyran (THP), R₂ is—OSO₃Na, R₃ is H, R₄ is NHSO₃Na, R₅ is methyl, and R₆ and R₇ are —CO₂Na;or (g) R₁ is H, R₂ is —OAcetyl or —OBenzoyl, R₃ is benzyl, R₄ is N₃(azide), R₅ is methyl, R₆ is —CO₂CH₂C₆H₅ and R₇ is —CO₂Me; andcombinations thereof.